German police is searching nationwide for a 23-year-old man under suspect after a lorry ploughed into a crowd at a Christmas market in Berlin on Monday night, killing 12 people and injuring many others, Xinhua reported.
According to information of German media Die Welt, the man who drove the truck to the Christmas market should come from Tunisia. In the footwell of the driver's cabin of the truck, identity documents of Anis A. were found.
The report said, the 23-year-old, born in 1992 in the Tunisian city of Tataouine, is said to be using at least four names and is considered a threat. Moreover, he allegedly has a residence in Berlin and in German state of North Rhine-Westphalia.
As local newspaper Bild reported, the documents were issued in the district of Kleve in North Rhine-Westphalia. Security circles assumed "imminent action" by the authorities in the state.
German Federal Public Prosecutor's Office announced on Tuesday evening that the suspect who had been temporarily arrested since late Monday evening due to the attack, was freed.
According to Die Welt, the Berlin police had admitted that they had arrested the wrong person. The real perpetrator is still "armed and still at large", and can cause new damages, the police was quoted as saying.
"We must assume it was a terrorist attack,"German Chancellor Angela Merkel said on Tuesday during a press conference, adding that the act will be clarified and punished "as hard as our laws require".
A series of attacks occurred in Germany this summer, raising concerns over the safety of the country.