French officers patrol Thursday outside a police station in Paris where a man with a fake suicide vest was killed. (Ian Langsdon/EPA)

The Islamist extremist who staged a failed attack on a Paris police station last week had been living in a shelter for asylum seekers in western Germany, police said, deepening fears that militants may be infiltrating Europe disguised as migrants.

The revelation that the assailant had been trying to pass himself off as an asylum seeker is likely to spur further debate about the vetting and processing of hundreds of thousands of migrants from the war-torn Middle East seeking sanctuary in Europe. The man had assumed several aliases and at one point claimed to be from Syria, according to police in Germany.

French authorities fatally shot him on Thursday, the first anniversary of terrorist attacks on a satirical publication in Paris and other targets, as he approached the police station brandishing a butcher knife and wearing a fake explosives vest.

Several assailants in the Nov. ­13 attacks in Paris, which killed 130 people, also are thought to have used the same routes being traveled by a record number of asylum seekers and economic migrants. They include at least two attackers who entered Europe posing as Syrian asylum seekers on the Greek island of Leros.

Acting on a tip from French authorities, German police searched an asylum center Saturday in Recklinghausen, in the state of North Rhine-Westphalia, where the assailant in last week’s attempted attack is thought to have lived. The man, according to the news outlet Die Welt, had registered in Germany under four aliases but had claimed legal asylum under the name of Walid Salihi.

Officials in North-Rhine Westphalia’s office of criminal investigations said Sunday that the assailant had probably carried out the deed alone. They said there is no evidence that any accomplices were involved or that anyone affiliated with the man is engaged in planning attacks.

Police released a photograph of the attacker and asked members of the public to share any information they have. Authorities said that between May 2014 and November 2015, the man had been charged with arms and drug violations, theft, and slander of a sexual nature. Criminal proceedings had been launched against him for allegedly drawing flags of the Islamic State militant group — which asserted responsibility for the Paris attacks in November — and displaying them in the refu­gee shelter. But the proceedings were discontinued.

Christoph Tesche, the mayor of Recklinghausen, said, “It is and remains our humanitarian and legal duty to give shelter to people fleeing their homes because they fear for their lives. It is also our duty — especially towards our citizens — to work very intensely together with all responsible agencies to prevent people with such intentions from hiding in our facilities.”

French officials initially identified the assailant as a petty thief from Morocco named Sallah Ali but later said he appeared to have been misidentified.

Authorities now say he may have been a Tunisian man named Tarek Belgacem, according to Agence France-Presse. After the attempted attack Thursday, police discovered a piece of paper on his body with an Islamic State flag and a handwritten note in Arabic asserting responsibility for the act. On Friday, Paris prosecutor François Molins said the man had a phone with a German SIM card.

The news that the man had claimed asylum in Germany comes as this nation is reeling from a spate of New Year’s Eve assaults and robberies targeting women in cities such as Cologne, Hamburg and Stuttgart. On Saturday, Chancellor Angela Merkel — who has maintained one of the most welcoming policies toward refugees in Europe — said she would back new laws aimed at quickly deporting asylum seekers and refugees who commit criminal offenses.

On Sunday, Cologne police said they arrested a 19-year-old suspected of stealing the cellphone of a 23-year-old woman on New Year’s Eve. The suspect’s name was not released, but police said he was a Moroccan citizen who had a criminal record dating to January 2013. As of Sunday, police said they have received 516 complaints related to the New Year’s Eve incidents, about 40 percent of them “sexual ­offenses.”

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