The Tunisian man who plowed a truck into a Berlin Christmas market had lived under 14 aliases and was so well known to German officials that a key counterterrorism committee had discussed his case seven times, suggesting the scale of the missed opportunities to thwart the Dec. 19 attack.

The fresh details about Anis Amri — shot dead in Italy four days after the attack — emerged Thursday during testimony in the regional parliament of North Rhine-Westphalia, where the suspect once lived. German officials have already said that Amri had previously been flagged as a terrorism threat. But Ralf Jäger, the state’s interior minister, described for lawmakers in Düsseldorf how the Joint Counter-Terrorism Center, an institution coordinating the work of Germany’s security agencies, had discussed his case repeatedly.

He also said that six months of surveillance had yielded nothing concrete, suggesting an operative highly skilled at hiding his resolve, or a failure of German law enforcement to adequately monitor him.

Speaking to reporters on the day of the hearing, Jäger said that German officials felt they did not have enough on Amri to detain him.

“We live in a legal state, where suspicion and hearsay do not suffice to take someone into custody,” he said. “And I think that is a good thing. A legal state needs to demonstrate in a court-proof manner that someone is planning a concrete crime.”

1 of 32 Full Screen Autoplay Close Skip Ad × Photos from the scene of the Berlin Christmas market attack View Photos The suspect in the attack, 24-year-old Anis Amri, was killed in a shootout with police in Milan on Dec. 23. Caption The suspect in the attack, 24-year-old Anis Amri, was killed in a shootout with police in Milan on Dec. 23. Dec. 23, 2016 Italian police officers stand next to the body of Anis Amri, the suspect in the Berlin truck attack, in a suburb of Milan. Reuters Buy Photo Wait 1 second to continue.

The case has become the latest example of stumbles by European authorities in the handling of terrorism suspects and has fueled more criticism of Chancellor Angela Merkel’s decision to open the door to more than 1 million asylum seekers, many of whom were inadequately screened, security analysts say. After a string of attacks in 2016, she described Islamist terrorism last week as being Germany’s “greatest threat.”

German authorities are continuing the search for possible accomplices in the December attack. On Tuesday, they arrested a 26-year-old Tunisian man at a Berlin migrant shelter, saying he had met Amri at a restaurant and had “intense” conversations with him around 9 p.m. on the night before the attack.

The Germans were not the only ones facing questions. Amri appears to have traveled across at least four neighboring countries before being shot by the Italian police four days after the attack. Security footage at Berlin’s Zoo train station showed him holding his index finger into the camera. Two days later, he was filmed in the Dutch city of Nijmegen, ­according to Frauke Köhler, spokeswoman for the federal attorney general’s office. He is believed to have arrived there from Brussels via Amsterdam.

Yet despite an international manhunt, Amri somehow managed to get as far as Milan, where two Italian officers questioned him, thinking he was a burglar. After he pulled a gun, they engaged him in a firefight. One officer was wounded, and Amri was shot dead.

Stephanie Kirchner contributed to this report.

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(Jenny Starrs/The Washington Post)

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