The first thing Daniel Georén registered was a cacophony of car alarms. It was 2am, and everyone in the attractive cobbled street where he lives in Malmö, Sweden, had been jolted awake by a giant explosion.

“The blinds shot up because of the pressure, and straightaway there was a small crowd of neighbours outside,” the 40-year-old wine merchant told the Observer a week after the blast.

Sweden bomb attacks reach unprecedented level as gangs feud Read more

The damage was still there to see: the door to his backyard had been blown off, his downstairs windows shattered, and his Volvo written off. Where the bomb had been planted in front of the house next door, there was a chunk of wall missing.

You might expect such a powerful explosion to be unusual in a middle-class district in otherwise safe, well-organised Sweden. But this bombing in November was one of three in the city in the space of 24 hours.

According to data released this month by the Swedish National Council for Crime Prevention, there were 257 crimes involving explosives in the country last year, a 60% rise on 2018. Gangland shootings are also shockingly high, with 320 reported last year, 41 of them fatal. As recently as Tuesday, there were twin explosions in two apartment buildings in a Stockholm suburb. The last blast in Malmö was on 10 January.

“These explosions in public places are a serious problem specific to Sweden,” Linda Staaf, the head of the Swedish National Police’s intelligence service, told the Observer. “It’s not normal to see these kinds of explosions in a country without a war.”

The wave of bombings and shootings is boosting the populist Sweden Democrats and the centre-right opposition, and weighing down on the Social Democrat-led government.

“People are being forced to flee their homes in the middle of the night because of bomb attacks,” Ulf Kristersson, leader of the opposition Moderate party wrote in Aftonbladet after Tuesday’s blasts, before accusing prime minister Stefan Löfven of “refusing even to admit the connection between failed integration and growing gang criminality”.

But Mattias Sigfridsson, deputy chief of Malmö’s police, claims that more than five years after the blasts began in 2014, police in the city are now starting to get a grip on the problem. “Since we’ve been working so hard on this issue, it’s been going down in Malmö,” he said.

In response to the blasts that rocked Georén’s street, police launched a national effort called Operation Hoarfrost. “We have sent police from all over Sweden to Malmö and Skåne,” said Staaf, who was appointed the operation’s deputy incident commander. “There are more police on the streets, more police investigating the crimes. You can never be sure that it is because of our work, but the situation is better there now.”

Sigfridsson stressed that the shocking recent statistics covered crimes registered, not explosions. “If we file a complaint against someone who’s been trying to organise an explosion, then that is recorded: those figures aren’t explosions that have occurred. In many cases, it’s because of our proactive prevention.”

So while the number of crimes recorded involving explosives nearly doubled in Malmö last year compared with 2018, the number of blasts fell to 36, down 38% on the city’s 2017 peak. And police are starting to put bombers behind bars. The week before last, three members of the loose-knit gang behind three of the recent bombings were jailed. Just before Christmas, a man was found guilty of bombing a nightclub in March.

Facebook Twitter Pinterest Police investigate the scene of an explosion at the entrance of a nightclub in Malmö in March 2019. Photograph: TT News Agency/Reuters

According to the prosecutor in the first case, at least two of the bombings stemmed from a conflict between the 28-year-old leader of one of the city’s loose-knit gangs and his family. One of the attacks hit a corner shop run by his elder brother, whom the gang leader had fallen out with because he hadn’t visited him in prison after he had been arrested in 2018 on suspicion of ordering the murder of their former brother-in-law.

The suspected gang leader was not in the end convicted for the murder, which the prosecutor claimed was in revenge for divorcing his sister. But, seeking revenge on his family, he had begun calling in real or imagined debts. Weeks before the attack, he texted his brother, asking him to “be nice” and give an associate the 750,000 krona (£60,000) he believed he owed. “Then we can solve everything between us in the family when the time is right, inshallah.”

Five days after the shop blast, an apartment belonging to the 28-year-old’s cousin was bombed. When police arrived, they found the 18-year-old who had planted the explosives lying by the door with his arm blown off and an eye missing, having misjudged the detonation.

According to the policeman who took the cousin in for questioning, he babbled in the car that the blast must have been ordered by the 28-year-old, who was angry with him for letting the brother-in-law who was later murdered live with him after the divorce. He had received messages, he said, warning that he would “pay in blood” for what he had done if he did not buy himself out of the “blood debt” with a 2m krona (£160,000) payment.

The explosions are mainly to threaten others … to scare them in some way Mattias Sigfridsson, Malmö police

In their investigation, police built up a mass of evidence: they found a weapons store in the attic of an apartment building containing two submachine guns, ammunition, detonators, plastic explosives, and the thermoses used as casings for the bombs. They filmed the 28-year-old’s associates entering the weapons store, and buying thermoses, being careful not to leave fingerprints on them, and they found DNA evidence tying his associates to the scenes of the crime.

Christoffer Östlind, the prosecutor, even cross-examined the man who had pulled the trigger in the 2017 murder of the brother-in-law. The man told the court via a video link from jail that the gang leader had both ordered the killing and provided the weapon.

But while mobile phone signals showed the 28-year-old had visited the sites of both explosions on the day, every witness who had accused him withdrew their testimony in court. “All the people who came to court were afraid to accuse [him],” Östlind told the Observer. “They knew that if they told the truth there was a big chance something bad would happen to them.”

So when the court ruled on 10 January, it jailed three of the gang leader’s associates for between two and four years each. However it said there was insufficient evidence to jail the leader himself, and he was sentenced to just one month in prison for making “illegal threats”.

As for the nightclub bombing, the prosecutor told the court that the perpetrator planted the bomb simply because he had been barred from entry a few days previously.

Sigfridsson said the bombs often seemed to be a reaction to such minor slights. “It doesn’t have to be a very big conflict. If you have a problem with an old girlfriend, or someone doesn’t say hello in the right way, you might commit a very serious crime.”

The bombs are also usually timed and placed in such a way that no one is killed or injured. “What we see is the explosions are mainly in some way to threaten others… to scare them in some way,” he said. “They’re not doing this to hurt one another.”

The mystery remains as to why explosions are so prevalent in Sweden’s cities, where crime rates are otherwise relatively low. “If we compare ourselves to cities in Germany with the same ethnic population, there are huge differences,” Sigfridsson said. “We are trying to get academics to look at why Sweden is the way it is.”

Staaf suggests it may simply be a warped fashion. “People in these networks are influencing each other,” she said. “They think that this is the way you should act if you are involved in criminal conflicts. It’s a trend.”