A man drowned in a water tank in an abandoned building on Deligiorgi Street in the central Omonia area of Athens late Sunday, police said on Monday.
The victim had allegedly been trying to run away from a man whose phone he had just stolen, police said.
It was not clear why he climbed into the water tank.
Police rushed to the scene after his cries for help were heard by passers-by on the street outside.
One officer dived into the water, but was unable to save him.
His body was later retrieved by firemen.