Mohamed Merah, a 23-year-old petty criminal, spent much of the last 36 hours of his life crouched over a laptop in his small apartment in the south‑western French city of Toulouse. It was March 2012. Outside, armed police and journalists gathered. Merah reheated frozen food in a microwave and checked his weapons. He spoke with negotiators and described how he had travelled to Pakistan a few months earlier to receive some desultory training from a faction linked to al-Qaida. He also explained, incoherently, why he had killed seven people over the previous two weeks in a series of shootings. But most of the time, Merah worked on his computer.

Just a few hours before he was killed by armed police after a sustained firefight, Merah finished editing a 24-minute video clip. It was a compilation of images from the GoPro camera that he had attached to his body armour before each of his killings. GoPro primarily caters to practitioners of extreme sports who wish to obtain point-of-view footage of their adrenalin-charged exploits. Merah had filmed his preparations, the murders themselves and his motorbike getaways. His first three victims were off-duty soldiers, two Muslims and a Catholic. The others, a rabbi and three children, had died when he had attacked a Jewish school. The images showed how Merah had chased and caught one of those children: eight-year-old Miriam Monsonego, who had hesitated for a second when others ran, reluctant to abandon her school bag. Merah grabbed her by the hair, changed his weapon when the first jammed, and then finally shot the girl in the head.

Roughly 24 hours after police located Merah and surrounded his building, he managed to slip through a gap in the security cordon. He did not take the opportunity to escape. Instead, he walked to a postbox, deposited a package containing a USB stick with the video on it, and then returned to his home to await his own death.

The package he dropped into the postbox was addressed to al-Jazeera, the Qatar-based TV network. Merah was confident that al-Jazeera would broadcast the material because, in his words, it constantly showed “massacres and bombs and suchlike”. In fact, al-Jazeera did not show any of the clip because, the network said in a statement, Merah’s images did not “add any information” not already in the public domain and breached its ethical code.

The network’s decision did little to diminish the stream of horrendous violence that has been disseminated by Islamic militant groups and individuals in recent years. Since Merah’s death, the use and broadcast of graphic and violent images has reached an unprecedented level. Much of this is due to the emergence of the Islamic State (Isis), which launched its campaign to carve out an enclave in eastern Syria and western Iraq at around the time Merah was planning his killings. But much is also a result of the capabilities of the new technology that Isis has been able to exploit.

New technologies have not only made it possible to produce propaganda with astonishing ease – they have also made it far easier to disseminate these films and images. Isis videos include the executions of western aid workers and journalists, Syrian government soldiers, alleged spies and suspected homosexuals, a Jordanian pilot, Christian migrant workers, and others. Some have been decapitated, others shot, blown up, hurled from tall buildings or burned alive. A representative sample can be viewed, entirely uncensored, with a few simple clicks on the device in your pocket or on which you may be reading this. One such video appears on a popular British newspaper’s website after an advertisement for family holidays. The scenes of actual killing have been removed but little else.

Though it accounts for only a fraction of the overall propaganda output of Isis, this material has had a disproportionate impact, just as planned. Many of the clips serve a dual purpose, inspiring one group of people while disgusting and frightening another. One recent video opened with TV news coverage of the aftermath of the attacks in Paris in November, which left 130 dead. It then segued into footage of some of the men who were responsible, filmed in Syria before the operation. Wearing lapel microphones, they made threats against the west and then executed prisoners with knives. Another video showed a child, possibly the son of a Briton currently in Syria, detonating explosives that destroyed a car in which four alleged spies were seated. A third recent video showed a competition involving young children who raced through a labyrinth to reach captives, who they then shot. The violence depicted in these clips is becoming ever more baroque, the choreography of the savagery increasingly elaborate.

As such material began to reach our screens around 18 months ago, many expressed shock that Isis had exploited modern media technology for the purposes of propaganda. Such surprise appears rooted in the expectation that a supposedly “medieval” organisation would use “medieval” means. The group’s use of social media marks it out from predecessors such as al-Qaida. So, too, do the high production values and visual language derived from video games and Hollywood blockbusters. But terrorists have always exploited the latest technologies, whether dynamite or digital communications. And the group’s exploitation of cutting-edge contemporary media falls squarely within the long tradition of terrorist organisations rapidly adapting to change.

The new wave of violent propaganda has prompted much debate about the role of Isis videos in attracting militants, as well as the degree to which the media itself is responsible for providing terrorism with the “oxygen of publicity”.

But certain crucial elements have received less attention. One is the way in which new technology has shaped both the media itself and terrorist organisations in ways which are strikingly similar. A second is the role we may be playing – albeit unthinkingly and against our better intentions – in the evolution of the media strategies of the very groups we so abhor. Neither of these possibilities is particularly comfortable to contemplate.

On the eve of the 9/11 attacks, Osama bin Laden left Kabul and headed south-east to a remote valley in eastern Afghanistan. Among the small convoy of vehicles in which he travelled was a “media truck” that had been prepared on his orders a few months earlier. A young follower had managed to equip a minivan with satellite television receivers and radio antennae to monitor broadcasts. Bin Laden’s aim was to follow news coverage of the operation in the US as the planned strikes unfolded.

A man in Guatemala watches the destruction of the World Trade Center live on television. Photograph: Andrea Nieto/Getty Images

The relationship between terrorism and the media has long been clear. Terrorists aim to provoke irrational fear among large numbers of people in order to influence policymakers and thus advance their goals. Terrorism, in its modern form, has its origins in the mid to late 19th century – in the same era that saw the spread of both the mass media and democracy. Without the media, only a small number of people would know that an attack has taken place, and without democracy, those wielding power would have little reason to heed the sentiments that such violence provokes.

Terrorism continued through the first half of the 20th century, though it was overshadowed by major global conflicts between 1914 and 1945. A new surge of terrorist violence came in the immediate postwar era. This coincided with the arrival of televisions in US and European homes. Those fighting colonial regimes immediately recognised the implications. In 1956, the Algerian political activist and revolutionary Ramdane Abane wondered aloud if it was better to kill 10 enemies in a remote gully “when no one will talk of it” or “a single man in Algiers, which will be noted the next day” by audiences in distant countries who could influence policymakers.

The next major wave of terrorist violence to emerge from the Middle East began in the late 1960s but peaked in the following decade with a series of high-profile assassinations, airplane hijackings and bombings. In Inside Terrorism, Bruce Hoffman, one of the most respected academics working in the field, points out that this coincided with a series of technological innovations that made it possible to send images cheaply and rapidly across great distances. This allowed American TV networks to provide much more comprehensive, and more gripping, coverage of events across the world. In 1972, members of the Palestinian Black September group attacked Israeli athletes at the Munich Olympics, the first games to be broadcast live and the first to be the target of a terrorist attack. The cameras inevitably switched their focus from the sports to the ongoing hostage crisis. Over the next decade, kidnappings and hijackings became rolling stories with vast audiences following every development.

When Al-Qaida was founded by Bin Laden and a few other veteran extremists in 1988, the means of mass communication in the Islamic world and beyond were still dominated by states and large corporations. Only these could afford the infrastructure required to produce material and broadcast it to millions of people. Most of the time, extremists had to make do with pamphlets, audio cassettes and, eventually, videotapes passed from hand to hand, circulated in mosques or sold in specialist shops. Though these could have a potent mobilising effect on those already disposed to participation, there was still no effective way for extremists to reach a bigger audience without somehow convincing state officials or TV stations to broadcast their statements or news of their violent acts. The former was inconceivable. The latter, though fraught with difficulty, at least allowed them to get some kind of message across to millions.

From the beginning, Bin Laden had understood the importance of the media. During the war against the Soviets in Afghanistan in the 1980s, he had helped fund and organise the propaganda efforts of the Afghan mujahideen factions. He also constructed his public image by inviting carefully selected film-makers to spend time with him during his rare trips to the front lines. During his time in Sudan from 1991 to 1996, Bin Laden ordered a fellow Saudi called Khalid al-Fawwaz to establish a media office in London. But tedious and verbose written statements, such as Bin Laden’s 1996 “Message to His Muslim Brothers in the Whole World and Especially in the Arabian Peninsula, attracted little attention. Issued just weeks after the al-Qaida leader had returned to Afghanistan, this call to jihad was supposed to rouse the masses of the Ummah, the global Muslim community. Its failure was manifestly obvious.

By the late 1990s, new opportunities were opening up. Local-language satellite TV channels had begun to spread across the Islamic world, allowing unprecedented numbers of people to watch content that had not been vetted by government officials. These networks soon became hugely popular. Al-Jazeera led the way, but was only part of a broader phenomenon. These channels showed images of violence against Muslims in places such as Kosovo, Chechnya and Gaza. They also brought lively and often controversial televised debates into millions of homes, coffee shops and offices.

Bin Laden, now back in Afghanistan, was swift to grasp the potential of the new satellite and cable networks. In the years immediately before 9/11, he gave a string of carefully choreographed press conferences to invited local and global press, despite the Taliban having prohibited communication with international audiences. Bin Laden’s efforts, however, were primarily directed at those broadcasting to the Islamic world. A series of videoed statements were couriered to al-Jazeera’s offices in Islamabad.

But, once again, these videos did not have the effect that Bin Laden intended. The coverage of these often rambling communiques was, as it always had been, determined by editors, who made similar decisions, whether they were based in the Gulf or western capitals. Bin Laden’s productions would be broadcast only as short excerpts. Some were delayed for weeks or months, others were simply not deemed newsworthy at all. An al-Qaida courier I interviewed in Pakistan a few weeks after the 9/11 attacks described Bin Laden’s frustration at his continued failure to communicate his message to the widest possible audience: “Every time I took a new tape, he told me how important my mission was, and how this time, the Muslims of the world would finally listen, and how I must absolutely deliver the tape to the right people.”

Osama bin Laden makes one of his many broadcasts. The al-Qaida leader became frustrated when many were ignored or cut by news organisations. Photograph: AP

The lessons for extremists were clear. Spectacular attacks were needed – events so shocking that no news editor could ignore them. But the practical demands of planning and executing high-profile attacks of this sort required a significant investment in training and infrastructure. The double bombings of US embassies in east Africa in 1998, the attempt to sink a US warship off Yemen in 2000, and the 9/11 attacks themselves were all complex operations. They needed a stable and safe location from which they could be planned. Contrary to popular belief, Bin Laden did not operate out of caves during this period. Quite apart from being extremely uncomfortable, this would have precluded most forms of communication. Instead, he lived with an extended family and many retainers in a series of fairly extensive barracks, compounds and camps. The camps played a vital role, offering training facilities that attracted hundreds of potential recruits. The best of these recruits, often hardened in local battles, could then be selected for advanced instruction.

It is often thought that the existence of these camps led to the attacks, but the truth might be the reverse. The need to do something that would dominate news bulletins around the world led to a strategy of spectacular violence, which in turn meant that the camps were essential. Indeed, before 9/11, al-Qaida focused all of its energies on facilitating such operations; setting up cells in east Africa, the far east, Europe and elsewhere. Any desire to take and hold territory was set aside.

Though the aim of the organisation was in part to mobilise, radicalise and instigate through spreading an ideology, authority within al-Qaida remained centralised and hierarchical. Local groups sent in, or physically brought in, proposals which were then vetted by Bin Laden or his associates. This structure mirrored that of most media organisations of the time: a central, tightly controlled core running a series of subsidiary operations often some distance away, all committed to spreading a particular message to as many people as possible. It is not for nothing that both TV channels and terrorist organisations are frequently referred to as networks.

With the 9/11 attacks Bin Laden succeeded where so many other terrorists had failed: he captured the undivided attention of the entire planet – in real time. Bin Laden himself, reliant on his “media van” in eastern Afghanistan, could only hear the reports of the attacks in New York and Washington on the BBC World Service. But he and his followers hailed the strike as a great victory.

For several years to come, Bin Laden’s every utterance would be broadcast, often in its entirety, by the world’s media, then picked over, discussed and repeated. The images of the spectacular attacks themselves would be played and replayed too. No single terrorist before or since has attained the power to communicate with so many people. Yet within years al-Qaida’s strategy would look distinctly out of date.

When Islamic extremists seized control of Falluja, the western Iraqi city, in late 2003, they set up training camps, bunkers, communications centres, ammunition dumps, makeshift prisons and at least one TV studio. This studio, as US marines discovered when they recaptured the city a year later, was equipped with video cameras and editing equipment. On one blood-spattered wall hung the banner of the local affiliate of al-Qaida, which was led by a former street thug from Jordan in his mid-40s, known as Abu Musab al-Zarqawi.

Zarqawi had little time for the intellectualism of the older al-Qaida leaders to whom he owed nominal allegiance. He had built his reputation through a combination of proven organisational ability and brute savagery. This heavily-tattooed ex-convict was nonetheless one of the first extremists to recognise and exploit the digital revolution.

The arrival of the digital media world in the mid-2000s dramatically altered the way terrorists operate. In a few years, many of their most intractable problems simply disappeared.

The first major shift involved the introduction of cheap portable cameras and editing software that required only the most basic skills to create professional-looking content. No longer was there any need for equipment costing tens of thousands of dollars, nor stacks of blank videotapes, nor bulky editing or copying machines. There was also no need for networks of human couriers to physically deliver content to media organisations.

Crucially, Zarqawi, or perhaps one of his associates, realised that extremists no longer had to make content that appealed to news editors in distant offices. They could create their own productions, designed to speak directly to the exact people they wanted to speak to, then broadcast them via the internet. They did not need a plane flying into an office block or a bomb on a train in a western capital to get their message across. There was also no need to make the massive investments – and take the huge risks such an operation required. The training camps Bin Laden had set up in order to carry out spectacular terrorist attacks were no longer necessary. Groups like Zarqawi’s could make do with a much less vulnerable, lighter infrastructure.

Another thing that Zarqawi and his fellow insurgents could stop worrying about was what might be considered too gruesome to broadcast on television. In May 2004 Zarqawi produced a clip showing the execution of a Nicholas Berg, a young American contractor who had been working in Iraq. It was not delivered to mainstream organisations. Instead, it was uploaded to a militant website. The oft-cited figure of half a million downloads within 24 hours may be exaggerated, but it is clear that this footage reached a much greater audience than any comparable material – such as the video of the murder of the American journalist Daniel Pearl in Pakistan 2002 – had ever done. The clip of Berg’s death made Zarqawi, who had previously been viewed as a marginal figure, one of the world’s most prominent Islamic militants.

Abu Musab al-Zarqawi, the leader of an al-Qaida affiliate in Iraq, used video to promote his reputation for brute savagery. He was killed by US forces in 2006. Photograph: AP

If the extremists faced the same disadvantages as anyone else broadcasting online – the competition for attention was much greater, for example – they also reaped the rewards. And if established mainstream media organisations were to suffer in this digital revolution, so too were their equivalents among terrorist organisations. When Zarqawi’s superiors in al-Qaida, who were still working to an older model of media production, urged him to be more restrained, he simply ignored them.

By the time Zarqawi was killed by an airstrike in 2006, new media technology was being widely exploited by extremists and insurgents. Lightweight cameras meant that images of ambushes and raids could be easily captured. Entire cable and satellite TV channels emerged devoted solely to broadcasting clips of attacks on international or Iraqi government forces. The internet allowed such material to be viewed by an even larger audience. As intended, the stream of footage, which frequently featured improvised explosive devices destroying US armoured vehicles and the bloody corpses of Iraqi policemen, boosted the morale of those opposed to the US presence and the rule of successive governments in Baghdad, while undermining that of supporters of either.

This was only the first phase of the revolution. A series of interlinked developments deepened and broadened change. First came the miniaturisation of video cameras to the point where they could be combined with mobile phones. A few months after Zarqawi died, Saddam Hussein was hanged, supposedly secretly. But a mobile phone was used to secretly record a three-minute video of his execution.

In the past, it would have been easy to at least restrict circulation of this footage. But no longer. The clip was leaked and, via the internet, viewed by millions. As commentators have pointed out, the clearly audible sectarian slogans shouted by guards undid the careful framing by the US and local authorities of the hanging as a climactic act of national liberation.

Later came the rise of smartphones, which allowed hundreds of millions of people in the Islamic world – many of whom had previously not enjoyed access to the internet – to view whatever they wanted, wherever they wanted. Smartphones also contributed to the growth of social media organisations such as Facebook.

As ever, the technological changes took some time to have an impact. It was not the jihadis who first exploited these innovations effectively but the secular, pro-democracy activists involved in the Arab Spring. As veteran rulers were deposed by crowds of protesters in Tunisia and Egypt, however, the significance of the new technology for militants became more obvious. One former extremist involved in the killing of President Anwar Sadat in 1981 told a reporter in Cairo almost exactly 30 years later that if there had been Facebook, the assassination of the Egyptian premier would not have been necessary. His logic was simple: if social media had existed to offer an alternative, and much less risky, means of mobilising supporters and sending a message to enemies, there would have been no need for Sadat’s assassination, which was carried out during a military parade in front of scores of TV cameras with the objective of sparking a broad uprising.

Bin Laden, born in 1957, and his ageing close associates were among the slowest to grasp the opportunities this new technology offered. The first extremist group to fully exploit the digital revolution was Isis, under the leadership of Abu Bakr al-Baghdadi, who was born in 1971. By the end of 2011, the group was sending clips of killings of Iraqi government soldiers and police to the phones of the victims’ erstwhile comrades. These multimedia messages had a predictably devastating effect on their recipients’ will to fight. Other material, including a series of carefully produced short films with titles such as The Clashing of the Swords also began to circulate widely. All the major social media platforms were exploited in different ways. The amputation of the hand of an alleged thief in Syria was live-tweeted. One innovation, noted by terrorism expert JM Berger, was an app designed for Twitter called The Dawn of Glad Tidings, which allowed Isis to build up huge surges of retweets around particular topics.

During this period, when it came to attacking western targets, Isis and other groups encouraged individuals to act alone. This strategy, which some analysts called “leaderless jihad”, was based partly on theories developed in the early 2000s by an independent militant strategist known as Abu Musab al-Suri. His adage was that extremist activists needed “principles, not organisations” and should be empowered to act as individuals, guided by texts they could find online, without necessarily belonging to any one group.

Suri set out his ideas on the new style of terrorist violence in an extremely long book entitled A Call to a Global Islamic Resistance that he posted online shortly after the London bombings of 2005. Since then, the “lone wolves” associated with his teachings have become a reality. The massive single strike in the west has, largely, been replaced by a series of smaller ones by independent actors who attack locally. The stabbing of an MP by a young British woman in 2010 and the killing of an off-duty soldier in London in 2013 the same year are two examples of such attacks. None of those involved – a student, a pair of friends – were linked to any terrorist organisation. Even the men who killed 12 people in Paris in January 2015, in attacks on the offices of the satirical magazine Charlie Hebdo and a Jewish supermarket, had only tenuous links with established groups. One of them, Amedy Coulibaly, received retrospective endorsement from the Islamic State. Another had some contact with an al-Qaida-linked cleric several years before. (The bombing of the Boston Marathon in 2013 was a hybrid attack – the Tsarnaev brothers were not connected to a terrorist organisation but they struck a high-profile target with the intention of causing mass casualties.)

The result is that, if terrorism is “theatre”, as the scholar Brian Jenkins said in the 1970s, Islamic extremist violence now takes the form of a stream of unpredictable, inter-related pop-up events that attract fleeting attention, rather than a programme of large-scale, unique productions. Terrorist communication takes place through multiple channels, all working simultaneously. The organisation of plots is increasingly peer-to-peer, not centralised. Once again, the structure of the terrorist groups, increasingly diverse, fragmented and dynamic, mirrors the changing structure of the media whose attention they seek.

It is difficult to predict what will come next. It now appears that Isis, having hitherto relied almost exclusively on “leaderless jihad” for attacks in the west, are also interested in mounting spectacular strikes of a type reminiscent of those conducted by al-Qaida. We have seen examples of both strategies in recent months. The attack in Paris last November was perpetrated by young men of immigrant backgrounds from Belgium and France who had come together in Syria in one of the camps that Isis has established in the last 18 months. They appear to have been trained there and dispatched into Europe specifically for the Paris operation. But the young couple who killed 14 in San Bernardino, California, in December had no prior contact with Isis, and only pledged allegiance to its leader (on Facebook) minutes after their attack was under way. Again, as with publishing today, the older “legacy” terrorism exists alongside the less structured “new” terrorism.

Whatever the future holds, we can be sure that violent extremists will also exploit new media technology whenever it becomes available. It may not be long before an individual attacker, or a terrorist group, produces a live stream of an attack, with images broadcast from the point of view of the killer. The technology already exists. When it happens we will be forced to decide whether or not we will watch.

We have already come very close. In September last year, a journalist and a cameraman were shot by a colleague during a live broadcast of an interview in Moneta, Virginia. Though the network cut the broadcast, Vester Flanagan had also used a GoPro-style camera to capture point-of-view images of the attack, and then posted a 56-second video of the murders to social media. Both Twitter and Facebook rapidly removed Flanagan’s profile – the former within eight minutes of the footage being posted – but his use of contemporary media ensured that what was otherwise a shocking, but fairly banal shooting in the US received global attention. Newspapers around the world showed images of the killings, all grabbed from Flanagan’s own video. Many publications put the pictures on their front pages. As for the general public, Flanagan’s tweet – “I filmed the shooting see Facebook” – was rapidly and widely disseminated. Many people inadvertently watched the images as a result of the autoplay function on social media platforms. Still images were viewed by many, many more.

One element that is striking about the Paris attacks in November is that the killers did not carry cameras, or apparently make any other attempt to generate content that could be used to publicise their actions. This may simply have been an oversight, a deliberate tactical or strategic decision, a consequence of their intention to die in the assault – or it may have been a reaction, possibly unconscious, to the new media environment in which terrorists operate.

Tashfeen Malik and Syed Farook on CCTV at O’Hare airport in Chicago, in 2014. Eighteen months later they killed 14 people in San Bernardino, California. Photograph: Reuters

Back in 2013, the killers of Lee Rigby prepared a statement that they read to members of the public passing the scene of the attack. Those people, inevitably, had mobile phones with cameras, which, equally inevitably, they used. The most striking images of the murder were those recorded by one such passerby showing one of the killers, his hands bloodied, delivering a rant about the inequities of western foreign policy and apologising that “women and children” had been forced to witness such violence. The images made front pages and were broadcast at length on the television news.

The most powerful images of the Charlie Hedbo attacks also came from a passerby. A neighbour used his phone to capture the moments when the gunmen effectively executed a wounded policeman on the pavement outside the magazine’s offices. These, too, were broadcast, at least in part.

As for November’s Paris attacks, three clips have been viewed by many millions of people. One was an excerpt from CCTV footage in a bar. It was obtained by the Daily Mail and broadcast by multiple news organisations, including the Guardian. It showed a gunman’s weapon jamming as he sought to shoot a woman. Other footage that reached millions worldwide was the mobile phone video of terrified concertgoers, some badly wounded, one heavily pregnant, trying to flee the venue during the attack. Perhaps the most memorable of all was the video of the crowd at the Bataclan concert hall in the moments as the first shots rang out. It was filmed by a member of the audience. Scores of those seen dancing or cheering would be dead within hours.

All this material owes its existence to the actions of those who were directly or indirectly targeted. This suggests a deeply disquieting prospect. The Paris attackers may not have made any provision for capturing images of their operations because they did not need to. They, or more likely their commanders, knew that they could rely instead on the unprecedented prevalence of cameras, and our apparently insatiable appetite for sharing the images they produce, to do the job for them.

The New Threat by Jason Burke (Bodley Head, £16.99). To order a copy for £12.99, go to bookshop.theguardian.com or call 0330 333 6846.

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