Wardens at Bochum prison went to check the 50-year-old man's cell after he failed to turn up for breakfast – and found the sawn-off bars at his open cell window.
A manhunt was launched for the prisoner who has been in jail since 1983, for crimes including a robbery in which a person died, for which he was given a life sentence.
“I don't know whether he received a cake recently, but the entire incident is like something out of a film,” a spokesman for the Bochum police told The Local on Monday.
“We don't know where he got the saw from, but he sawed through the bars on his window and escaped onto the roof. His cell was on the top floor so he was able to get onto the main roof of the building.”
Authorities thought he must have jumped from the main roof onto the flat roof of another building and from there, over the perimeter wall, where they thought an accomplice had been waiting.
But in the afternoon a sharp-eyed prison employee found the man in an attic room, a police spokesman said.
“We can breathe a big sigh of relief,” the spokesman told The Local.
“He is really a dangerous man and we were very worried at the idea of him being free.”
The man put up no resistance when he was found. An investigation will be launched to try to find out how he managed to get hold of a saw.