These CCTV images show a hit squad on their way to murder a Hamas commander in Dubai. As police close in on the prime suspects, Gordon Corera investigates the organisation behind the killing, Israel's notorious Mossad

15:30 Mahmoud al-Mabhouh is trailed by the two 'tennis players' as he walks to his room. After learning his room number, the team checks into the one opposite

It was a late-morning phone call from a concerned wife on January 20 this year that first alerted the Dubai police to the case of Mahmoud al-Mabhouh. She had been unable to reach her husband, who was travelling in Dubai on business. The news was of no interest in itself, but what made the police pay attention was the man's name - Mabhouh was a military commander in the Palestinian movement, Hamas.

A police patrol was sent to the glitzy, chandeliered Al Bustan Rotana hotel where Mabhouh had checked in the day before. By the time they arrived, hotel staff had already made their way to Room 230. The door was locked from the inside with a 'do not disturb' sign hanging on the outside. On entering the room they found the body of 49-year-old Mabhouh on the bed. Initially, it seemed he had died of natural causes, but in the weeks that followed, the police investigation would reveal that he had been murdered.

The target: Mahmoud al-Mabhouh, a military commander in the Palestinian movement, Hamas

The CCTV recordings that documented the moments leading up to the killing were shown on news bulletins around the world. It looked almost like an episode of 24 - although there was also something amateurish and comical about the footage. The two men in tennis gear who follow Mabhouh into the lift and watch as he approaches Room 230 of the Al Bustan Rotana look totally out of place; others involved seem to be wearing wigs or false beards.

As police pieced together what had happened, it became clear that the team of assassins had been sloppy at what spies call 'tradecraft' - the techniques of working undercover and hiding your tracks.

Sprinkles of blood were found on the pillow and there were bruises to Mabhouh's face and neck. There was also a needle hole in his right thigh and damage to the bed-head panel, which suggests that a struggle took place. The CCTV footage revealed teams of spotters signalling to each other both at the airport and then later at the hotel. It seems now that, 15 minutes after Mabhouh entered Room 230, the hotel received a phone call. There was a request to book Room 237 or 238, both of which were opposite Mabhouh's room. Room 237 was available.

Just before 4.30pm Mabhouh went out to have dinner in a shopping mall. Meanwhile, members of the assassination team entered Room 237. The hotel's computer system reveals that his door lock was tampered with before he returned at 8:30pm.

His killers were waiting. They injected Mabhouh with a muscle relaxant, which was designed to make it look like he had died of a heart attack. Mabhouh, incapacitated by the drug, was then suffocated with a pillow. It was replaced afterwards and a bottle of medicine for heart complaints placed by the bed. The killers then locked the door from the inside and hung the 'do not disturb' sign. By 8:46pm they were gone, scattering for the airport.

It didn't take long for the Dubai police to have their initial suspicions confirmed. In the old days, a well-forged document could get you a long way, but modern technology poses acute problems for spies. The advent of biometrics, CCTV and data mining using link-analysis software makes it much harder to maintain a false identity.



Two members of the assassination squad check in to the Al Bustan Rotana hotel, Dubai The target, Mahmoud al-Mabhouh, arrives at the hotel; his movements are being monitored by the suspected assassins

Two suspects dressed as tennis players cross the lobby and head towards the lift 18:32 While Mabhouh is out, two more members of the hit squad arrive at the hotel and get in position to make the kill

'The first eight of the team were identified within eight hours, and later we identified a further 11,' says Dr Hamiri of the Dubai police.

'One of them even brought his wife, who took part in the field surveillance exercise.' Police discovered that some of the team had visited Dubai previously, also at the same time as Mabhouh, suggesting a prior reconnaissance trip or perhaps an earlier murder attempt.

Hamiri says significant evidence has now been uncovered that links the attack to Mossad, Israel's secret service.



'The killers used prepaid debit cards issued on the same day by a company called Payoneer,' says Hamiri.



The company is run by an Israeli-American businessman with a background in the Israeli special forces. Many of the suspects also signed their passports in an identical way - with an initial letter, then a dot, then the surname.



'Also, what was a former Israeli diplomat doing behind Mabhouh when he went up to the second floor? And why did Israel ask us through a friendly state to refrain from publishing pictures of the individuals involved for "humanitarian" reasons? Can we establish that there was someone else behind this other than Israel?'



In apparently underestimating the Dubai police, and having so many of their people widely exposed, it appears that Mossad's reputation for being one of the world's most effective and ruthless secret services has been tarnished.

Pictures of four of the suspects involved in the killing of Mahmoud al-Mabhouh, taken from the forged passports



It was the passports that took a local police investigation global. At first sight they indicated that those behind the killing included British, Irish, Australian and German citizens. The Serious Organised Crime Agency (Soca) led the British investigation, and found that the passports weren't stolen, but were high-quality copies, with the names on the passports belonging to British citizens who lived in Israel. Details of the passports had apparently been copied when they had been handed over for inspection by Israeli immigration officers or other officials. The forged passports had all the same details apart from a new photograph and signature.

Israel maintains there is no proof that it carried out the killing. Even so, at home the revelations about Dubai were met with a wave of support.

'I'd say there's the same joy after a Mossad success as when Maccabi Tel Aviv (the basketball team) wins the champions league of Europe,' says Dr Ronen Bergman, who is writing a history of Mossad. 'This is Israeli pride, and one of the very few areas where Israelis feel that the government is doing the right thing.'

Mossad certainly has a special place in Israeli culture. It is perceived as the unseen watchman, the last line of defence and ultimately the avenger of those who wish harm on the country. Ephraim Halevy has seen it all from the inside. We meet early one morning at a large military base on the outskirts of Tel Aviv. On their way into the base, young Israelis on military service walk past a large complex housing a memorial to the fallen from Israel's intelligence services. Halevy speaks with an impeccable English accent, having been born in London in 1934 and educated in Britain. After watching the V1 and V2 rockets pummel London in the war, his family headed to Israel just before it became independent in 1948. He joined Mossad in 1961 when it consisted of only a few hundred people.



'There was an air of almost religious sanctity about Mossad, and when you served, it was a service for the nation, for the people. You were inculcated with a deep feeling and an almost messianic mission to preserve the essentials of the state of Israel.'

The sense of mission came from a generation who saw Mossad's task as to prevent another holocaust. They were willing to do whatever it took to achieve that. In the years after World War II, covert actions included 'cleaning up unfinished business'. One operation involved the kidnapping of Adolf Eichmann, an architect of the Nazi death camps, who was hiding in Argentina. He was returned to Israel, put on trial and hanged in 1962.

Many spy services carry out negotiations that their governments want to be kept secret and deniable - Britain's MI6 first made contact with the IRA and more recently with Colonel Gaddafi's Libya. Mossad's agents have always been Israel's secret diplomats.

'We were the shadow ministry of foreign affairs,' explains Halevy. 'If it was necessary to organise a secret meeting between an Israeli prime minister and somebody around the world, it was Mossad who had to do it to make sure secrecy was maintained.'



A poster at an anti-Israel demonstration in Iran, featuring Mossad chief Meir Dagan (centre)

Halevy himself engaged in secret talks with King Hussein of Jordan when the two countries were considering a peace treaty.

Throughout its history, Mossad has used London unofficially as a site for major operations. If you want to recruit an Arab as an agent, then it is far easier to approach them as they come out of Harrods than to try to do it in Cairo, Damascus or Riyadh.

Mossad built a fearsome reputation for its daring undercover work, and at one time its agents were considered among the world's best.

'They looked for honest crooks,' says Gad Shimron, who joined Mossad in the Seventies. 'They took people like me - obedient citizens of Israel - and taught us how to steal, how to kill and to do things that normal people don't do.'



Shimron was recruited into the elite operational unit of Mossad when he left the army. He was told that out of 1,500 candidates only ten were chosen. After nine months' training, six graduated into the team that carried out the most sensitive undercover operations.

'This is not Europe, our neighbours are not Swedes or Norwegians,' Shimron tells me in his Tel Aviv flat. 'We can win battles, but if we lose one that's the end of everything. We are aware that because of the extraordinary situation of the state of Israel in the world we, as members of the Mossad elite unit, were allowed to do things that our colleagues in MI6 or the CIA sometimes weren't allowed to do.'

Mishka Ben-David, now an established spy novelist, spent 12 years inside Mossad. He joined after replying to an advert in a newspaper and faced a year of training and selection, beginning with language, psychological and psychometric tests.

Those who passed the first stage were asked to undertake exercises on the streets of Tel Aviv. During one session, his trainer pointed to the balcony on the third floor of an apartment block in the city and said, 'In five minutes I want to see you on the balcony with the owner of the house. I want you to stay there with him for five minutes. Go.'



Onlookers at a recent car bombing in Lebanon, believed to be the work of Mossad

Ben-David looked round the area. 'Four-and-a-half minutes left,' said the trainer. Some of the balconies were being renovated. 'Four minutes.'

Ben-David walked up and knocked on the door. An elderly couple opened it a few inches, but clearly were reluctant to let him in.



'It's sad for you that you don't open the door because I'm from the municipality and we are trying to renovate all balconies in your buildings and the buildings around here,' he told the old couple.



The door swung open. Exactly five minutes after being set his task, Ben-David was on the balcony with the owner.

'What they wanted to see is that you can think fast, you can think right; that you do not have strange ideas like climbing the balconies underneath,' he explains.



'They want to know that you are bold enough and brave but you are not stupid. You won't do things that will make someone call the police.'

Those engaged in operational work are given a high degree of autonomy when sent out into the field on a mission.



'Once you send a team to some godforsaken place to do something, very often it's the team that will decide what the limits are,' says Halevy. 'There has to be a very deep camaraderie, but also a deep common understanding and common acceptance of what is the moral framework on which you are operating.'



The car bomb that killed the PLO's chief of security in 1979, which was blamed on Israel

Halevy became chief of Mossad in 1998, after an assassination operation went disastrously wrong. In 1997, two operatives were chased down the street and captured in Amman, Jordan, having just injected poison into the ear of Khaled Meshal, a senior figure in Hamas. The Jordanians, who had only three years earlier signed a peace treaty with Israel, were furious. In the end an antidote had to be delivered to Jordan and another senior Hamas figure released from an Israeli jail in order to secure the freedom of the two Mossad officers. Halevy brokered the deal and was then made chief, tasked with ensuring confidence in Mossad was restored.

Those two operatives had been travelling on Canadian passports and a diplomatic row ensued, much like the one that followed events in Dubai this year. British MI6 and American CIA officers can often travel under their true nationalities, but Israelis always have to pretend to be citizens of another state with a different name.

Working under a false identity requires constant vigilance.



'When you register in the hotel,' recalls Ben-David, 'you must stop for one second, take out your passport, look at your name and write it down because you may write down the name of the passport you used last week.'

Spies from all countries will sometimes use diplomatic cover, pretending to be regular embassy staff, or they might pose as businessmen, so called 'non-official' or 'natural cover'. This is riskier because if the agents are caught there is no diplomatic immunity to protect them from a jail sentence - or worse.

'All your adventurism fades once you have to board a plane under forged documents and go to Abu Dhabi or Tehran or Damascus,' explains Ben-David. 'When you know that if something goes wrong you may end up, if it's Abu Dhabi, in jail and, if it's Tehran, probably hanged.'



Adolf Eichmann on trial in Jerusalem in 1961

Israel and Mossad's top priority at the moment is not the Palestinian issue but Iran and its nuclear programme. One supplier was executed after he admitted working for Mossad and delivering equipment infected with computer viruses. Iran's centrifuges - used to enrich uranium - have been breaking down at an unusually fast pace or exploding, and some of the scientists involved have also met an untimely end. Although it sticks steadfastly to its policy of not commenting, Mossad is seen by many to be behind these mishaps.

The debates will continue about whether killings are really effective.

'You liquidate one terrorist, they are easily replaced - in most cases,' argues historian Yossi Melman.



'On the other hand, because you live in a rough neighbourhood, as we do in the Middle East, you have to send a message to the other side: that you are daring, ready to take risks and then kill your enemies because they try to kill you.'

Halevy insists that the idea that Israel behaves so differently from others is simplistic, especially in recent years when the 'war on terrorism' has led to the unleashing of the CIA.



'I think for their own reasons, and the nature of the threats that they are facing, they now do things which they wouldn't have done before,' he says.



The U.S. uses its drones in Pakistan to target Al-Qaeda suspects, and has added one of its own citizens, the former U.S.-based cleric Anwar Al-Awlaki, to the hit list. Is there a difference between smothering someone with a pillow in Dubai and dropping a bomb on their house in Waziristan?

Now it seems that the current head of Mossad, Meir Dagan, may not have his term in office extended. The Dubai police chief has claimed credit for forcing him out. Last month, a suspect using the name Uri Brodsky was arrested in Poland and charged with helping to falsely obtain a German passport linked to the Mabhouh killing.

'We will catch up with them, however long it takes,' says Dr Hamiri. 'They will not be able to remain living like nocturnal bats.' But even if their methods were exposed in Dubai, judged on past form, this will not be the last time that the long arm of Mossad reaches out across the Middle East.





Gordon Corera's 'Mossad' is on Tuesday, Radio 4 at 8pm





