Federal prosecutors, who handle terrorist attacks, have not yet taken over the case, he said.
But Fridayâs attack is sure to draw parallels to the Dec. 19 truck attack on a Berlin Christmas market carried out by Anis Amri that killed 12 and wounded dozens. Like the Hamburg attacker, Mr. Amri was known to the police and was facing deportation, but still managed to slip through cracks.
Unlike Mr. Amri, who pledged loyalty to the Islamic State group, the Hamburg attacker has been cooperating with the authorities, who were trying to acquire identification papers for him from the Palestinian Authority, which are required for his deportation.
The authorities were alerted to the possible radicalization of the man after one of his friends contacted security officials, said Torsten Voss, director of Hamburgâs state intelligence agency.
âA friend of his told us that this guy used to frequently drink alcohol, but recently he had noticed a change,â Mr. Voss said, describing the friendâs conversation with officials in August 2016. âThey said he started talking a lot about the Quran, stopped drinking alcohol and questioning many things.â
But last year an evaluator who interviewed the Palestinian â who spoke fluent English, Swedish and Norwegian â said that while he had mental health problems, he did not pose an imminent danger, Mr. Voss said.
The police have opened an investigation to piece together a motive for the assault, and they are looking through his cellphone and other items found in his home, said Kathrin Hennings, a spokeswoman for Hamburg police.
Germanyâs interior minister, Thomas de MaiziÃ¨re, expressed horror at the latest attack, but he…