In February, Anis Amri, a Tunisian refugee with a criminal past, was officially classified by the German authorities as a potential terrorist. For six months this year he was under near-constant police surveillance.

None of that helped. Amri went to ground and resurfaced last week as the man investigators believe rammed a truck into a Christmas market in central Berlin, killing 12 people.

The Europe-wide manhunt for Amri came to a bloody end on Friday morning when he was killed in a shootout with Italian police. But his death brings little closure for Germany. The country is still trying to understand how a known Islamist who had been on the authorities’ radar for months could have got away with such a deadly attack.

The Amri saga is deeply embarrassing for Germany’s police and intelligence agencies and has roiled its political class just months before Bundestag elections that will set Germany’s future course and could turn into a referendum on Ms Angela Merkel’s refugee policy and its implications for the country’s security.

Ms Merkel acknowledged the issue on Friday. The Amri case “throws up a number of questions”, she said, not only about the crime itself but about the time he had spent in Germany since arriving in July last year. She added that the government would “closely examine” whether laws needed to be changed in light of the findings.

For the Chancellor, who next year will seek a fourth term, the stakes could not be higher. Misgivings over her decision last year to open Germany’s borders to hundreds of thousands of asylum seekers already ran deep. With every terror attack committed by a migrant, that discontent will inevitably grow.

For the time being, though, the harshest criticism has been reserved for Germany’s security apparatus. “From the information we’ve been getting since yesterday, it’s just shocking the way the authorities worked here,” Mr Armin Laschet, deputy chairman of Ms Merkel’s Christian Democrat Union (CDU), told German radio on Thursday. Mr Christian Lindner, head of the liberal Free Democratic Party, spoke of “catastrophic mistakes”. “There has been a failure of government, and that cannot be tolerated,” he said.

Many consider that a wild exaggeration. “You can never have 100 per cent security in a country like Germany, where it is not the only objective,” said Dr Christian Tuschhoff, a political scientist at the Freie Universitat in Berlin. “In a democracy you have to have checks and balances, and sometimes they come at the expense of security.”

‘Loss of innocence’

Berliners certainly feel a lot less safe now than they did two weeks ago. The anxiety was palpable among crowds paying their respects on Breitscheidplatz, the square in the shadows of Berlin’s Kaiser Wilhelm memorial church where last Monday’s attack took place, and which is now covered by candles, flowers and cards of condolence.

Sandra, a hairdresser, says she was at the Christmas market just half an hour before Amri allegedly ploughed the stolen truck into the crowd. “Germany is now just as unsafe as everywhere else,” she said. “It’s like a loss of innocence.”

For Ms Merkel, the risk thrown up by last Monday’s outrage is that it undermines the credibility of the social compact she has offered the German people. On the one hand, she has asked them to join in the national task of integrating the one million refugees who have entered Germany since the start of 2015, a task she likens to the challenge of German reunification. On the other, she has promised that this huge influx can be absorbed without undermining security.

To try to convince people that she can achieve this, Ms Merkel has tacked sharply to the right, curbing access to asylum, promising speedier deportations of migrants denied refugee protection and those representing a “threat to public safety” — such as criminals and potential terrorists. She has also expanded video surveillance of public places, granted more money, equipment and powers to the police and even suggested banning the burka.

Such policies are designed to calm the CDU’s disgruntled rank and file and prevent even more defections to Alternative for Germany, an upstart right-wing party that seeks tough controls on immigration and has won seats in 10 of the country’s regional parliaments. Yet the Amri case shows how hard it is to deliver those promises. Authorities tried to deport him but failed, because he had no passport. He was investigated for terrorism, but charges were never brought. There was abundant evidence to tie him to radical Islamist networks, but not enough to justify his arrest.

The Amri case is all the more embarrassing because it comes after a string of incidents that have shaken public confidence in the security services. Germany’s Interior Minister Thomas de Maizière ordered an inquiry in October after a 22-year-old Syrian terror suspect accused of planning a bomb attack on a Berlin airport, Jaber Bakr, committed suicide in his cell. His death was a huge setback for those investigating the Islamic State’s activities in Germany.

Then there was the case of Hussein K, a 17-year-old Afghan arrested earlier this month in Freiburg on suspicion of raping and killing a teenage student. It later emerged he had been convicted of attempted murder in Greece in 2013 and sentenced to 10 years in prison. Released last year on parole, he disappeared and came to Germany.

Germany’s intelligence apparatus was already in trouble with the public after it emerged the BND foreign security service may have helped the United States National Security Agency spy on Germany’s EU allies. There have also been accusations of failures over the investigation into the National Socialist Underground, a far-right terrorist group that killed 10 people between 2000 and 2007.

The Amri case could do further damage. The 24-year-old arrived in Germany in July last year. But he set off no alarm bells with the authorities, despite the fact he had served four years in an Italian jail for crimes including arson.

Within months the German authorities had classified him as a “Gefahrder” — a radical Islamist who it is thought could carry out a terror attack.

The roughly 200 Gefahrders in Germany who are not already in custody are supposed to be under constant police surveillance. “In reality there are not enough officers to monitor them all,” said Mr Tuschhoff. “It’s extremely costly in terms of manpower and equipment.” Amri, who constantly moved around Germany using false identities, was particularly hard to track.

But Germany’s decentralised law-enforcement system, in which police and intelligence powers are devolved to the 16 federal states, does not help. The system is designed to prevent the emergence of a powerful all-German entity like the Nazi-era Gestapo or East Germany’s Stasi. But co-operation between the patchwork of different agencies can sometimes be lacking. Mr Klaus Bouillon, the Interior Minister of the small state of Saarland, recently called for a single federal criminal database to improve information sharing, replacing the 16 different systems employed now.

“We must make the Lander data systems compatible with each other,” said Mr Joachim Herrmann, Bavaria’s Interior Minister. “It’s a task that needs to be dealt with urgently.”

In 2004 the government created a Joint Counter-terrorism Centre, GTAZ, to better co-ordinate crime-fighting efforts between the federal and state authorities. But a lot still needs to be done. “The willingness to share information, especially between the domestic intelligence services of the various Lander, is not always that great,” said Mr Joachim Krause, head of the centre for security policy at Kiel University.

Radical links

In March the authorities began investigating Amri on suspicion he was planning a terrorist act, and placed him under observation. German media said intercepted communications show he had repeatedly put himself forward as a potential suicide bomber, while a police informer said he had approached him about procuring weapons. But there was not enough evidence to arrest him.

The Tunisian was also linked to the radical preacher Abu Walaa, who was arrested in November on suspicion of recruiting people to fight with IS in Iraq and Syria. Yet once again there was not enough evidence to detain Amri.

German authorities find it hard to deal with Gefahrders: In most cases they have not committed any crime yet, so they cannot be charged. But those who came to Germany as refugees can be deported.

That is what authorities tried to do with Amri. In June, his asylum application was turned down and shortly afterwards he was placed in a detention centre for refugees about to be deported. But he was released after just a couple of days. Hampering efforts to deport him was his lack of a passport and the Tunisian authorities’ refusal to recognise him as one of their own.

Meanwhile, Berlin prosecutors were continuing to monitor Amri, after receiving information he was planning a break-in to steal money for weapons. For months, his phone was tapped and he was put on round-the-clock surveillance. But the monitoring stopped in September after authorities found no evidence of terrorist activities. In November, GTAZ officials compared notes on him for the last time. Soon after, he disappeared from view.

It was by no means the last time Amri slipped through the net. Authorities were again under pressure on Friday to explain how the Tunisian managed to travel unhindered from Berlin to Milan. “That is for us one of the central objects of our further investigations,” said Mr Peter Frank, Germany’s federal prosecutor. He said a key focus would be whether he had a network of accomplices helping him flee.

Ms Merkel promised to “do everything” possible to ensure our state is a strong state” capable of protecting the country from further attack. But that might not be enough to reassure people like Sandra, as she braces herself against the December cold on Breitscheidplatz. Her life, she says, has changed since the attack. “I’m so much more anxious, always looking over my shoulder. It feels like nothing will ever be the same again.” FINANCIAL TIMES

ABOUT THE AUTHOR:

Guy Chazan is The Financial Times’ Berlin correspondent.