As soon as the mobile phone footage was played in the courtroom, members of the audience began to cry. The film showed fireman Gunter N. (33) arguing in a dark hallway with his neighbour Ewald L. (52) for three minutes. Then there were gun shots, the sound of a struggling breath. And then silence.

The fireman had filmed his own death. The killer, a marksman, has appeared in court in the German town Aachen. Gunter N., from Aldenhoven in North Rhine-Westphalia, never got along with his neighbour. They argued about loud music and Ewald L. always turned off his neighbours electricity in the hallway.

When the fireman came home one night in April and his electricity wasnt working, he rang on his neighbours doorbell. He had left the camera on his mobile phone running - just in case.

Then shooter Ewald L. opened his front door and fired nine times at his neighbour with a nine millimetre pistol. Gunter N. was killed instantly.

Ewald L. defended himself yesterday in court: He had a hammer in his hand. I had brought my pistol, and shot. Then he was just lying there. I let out a huge sigh as soon as I realised what had happened. But it was in self-defence!

But according to the prosecution, it was actually a malicious murder.

The post-mortem revealed that each shot had hit the fireman in the back. The police did find a hammer underneath the dead body, but believe that the neighbour planted it there. The case continues.