BERLIN (AP) — German prosecutors say they have closed an investigation of two Berlin police officials who were suspected of manipulating documents related to a rejected Tunisian asylum-seeker after he killed 12 people in an attack on a Christmas market in 2016.

Anis Amri hijacked a truck and drove it into the market in downtown Berlin, an attack that was later claimed by the Islamic State group. Public inquiries and German media have since uncovered a series of mistakes by officials who had been tracking Amri because he was believed to pose a public threat.

Two officials at Berlin's state criminal police office were investigated over documents which authorities suspected might have been tampered with after the attack. But city prosecutors said Wednesday they've closed the probe for lack of evidence.