Story highlights Anis Amri was a known "troublemaker," said state interior minister Ralf Jager

But he showed no signs of planning a terror attack

Berlin (CNN) Anis Amri, the man who drove a truck into a crowded Berlin Christmas market, killing 12 people, was illegally registered under "at least 14 known aliases" in Germany, lawmakers said.

In a report to the state parliament of North Rhine-Westphalia Thursday, state interior minister Ralf Jaeger said the Joint Terror Protection Center dealt with "Anis A" at least seven times.

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He was a known "troublemaker" who "traveled under at least 14 known aliases," he said. Recently Amri had been spending more time in Berlin and was being "monitored closely," though he showed no signs of planning a terrorist attack, the report found.

Amri, a 24-year-old Tunisian, was being considered for deportation at the time of the December 19 attack, but the legal requirements to deport him had not been met, Jaeger said.

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