The 18-page internal police memo cited in reports by WDR, NDR and the "Süddeutscher Zeitung" has given details of security surveillance of Anis Amri who was classified as dangerous in February 2016 and kept under close supervision. Surveillance was reduced in the weeks before he carried out the attack in Berlin.

Anis Amri was a known criminal who fled his native Tunisia to escape imprisonment for stealing a truck and in October 2011 was sentenced to four years in jail in Italy for an arson attack on a migrant holding center. He then moved on to Germany where he arrived in June 2015. According to the European arrest warrant issued by Germany in December, Amri used at least six different aliases and three different nationalities, claiming at times to be Egyptian or Lebanese.

Authorities in Germany considered that as a petty criminal, drug dealer and user who did not observe strict Muslim norms, he was not an acute risk, according to the memo. He was known to have used cocaine and ecstasy and may have earned money by selling drugs, according to newspaper "Die Welt." Amri may have been under the influence of cocaine and ecstasy when he carried out the December attack which killed 12 people and left 56 others injured.

He had been involved in a knife attack in July 2016 following a dispute over a deal.

The decision to withdraw close supervision by special forces was partly based on the fact that Amri had not observed Muslim ceremonies in September, which authorities took as an indicator he was not a strict Muslim.

He had links to radical preacher Abu Walaa, who was arrested with others in November on charges of recruiting volunteers to travel to the Middle East. Amri was dismissed by security forces as an "errand boy" despite being heard offering to carry out a "suicide attack" by a security team monitoring the Abu Walaa group's phones.

The evidence was passed on to Berlin where police believed Amri was planning a robbery to finance the purchase of weapons for a terror attack. But when no evidence of the attack was found, the surveillance was suspended.

Expulsion order

An expulsion order in June 2016 following the rejection of his application for asylum in Germany was not carried out due to a lack of personnel, according to the report. His expulsion was held up in diplomatic disagreements with Tunisia, which at first refused to accept he was one of its nationals as he had no valid identity papers.

There have been indications from the government of Chancellor Angela Merkel that there could be a parliamentary enquiry into the security and police operations in the case. Volker Kauder, leader of the parliamentary group of Merkel's Christian Democratic Union (CDU), said there were questions about the level of coordination between federal and state authorities. "If one of is of the opinion that more needs to be done here, I am open to a committee of inquiry," he said.

jm/kl (dpa, AFP)