The German Prosecutor’s Office offered on Wednesday a reward of up to 100,000 euros (over $104,400) for leads that would help detain the suspect in the attack, Tunisian national Anis Amri.
According to Süddeutsche Zeitung, the suspect is 178 centimeters tall, has black hair and brown eyes. He could be violent and armed.
Documents belonging to Anis Amri have been found in a wallet in the driver's cab in the truck, the media added.
On Thursday morning, the police searched in a refugee camp in Emmerich, North Rhine-Westphalia. Amri was officially registered in the city. There have also been raids in Dortmund.
The suspect in the Berlin attack made an application for asylum in Germany, however, it was rejected. Amri was to be deported this summer, but due to the lack of necessary papers he stayed in Germany.
The security authorities in Berlin and North Rhine-Westphalia were already investigating his involvement in the preparation of a serious criminal offense, Süddeutsche Zeitung reported.