Police and the public prosecutor's office are still investigating the details of the Unterföhring incident. According to the current state of knowledge and US media reports, the man who seriously injured a policewoman by shooting her in the head last Tuesday, and injured two more persons, was well-known by the US police.

He is said to have been involved in a custody lawsuit recently and got into trouble with US justice for the abuse of alcohol, theft and bodily harm.

The 37-year-old was identified as a Bavarian-born German citizen who had been living with his father in Colorado and was on a European trip. He flew to Munich airport from Athens on Monday and spent the night in the airport.

Witnesses say he was talking to himself in English as he rode the subway toward the city on Tuesday, then suddenly approached an innocent man and began punching him in the face.

Police were called and when the suspect got off at the suburban Unterföhring station, two officers began questioning him. Surveillance video shows one officer holding a pad of paper and pen taking notes when the suspect suddenly shoved him with "extreme violence" toward an oncoming train, Munich´s police chief Hubertus Andrae said.

In the following struggle the culprit grabbed the officer's pistol, and opened fire. He emptied the eight-shot magazine, hitting the female officer in the head and two by-standers in the arms and legs. He was put in psychiatric custody and has so far refused to talk to the police.

Andrae said police have video surveillance footage from multiple locations to review and are still working on a complete picture of how the attack unfolded, especially how the suspect was able to disarm the policeman.