An eight-year-old boy was killed by a train after he and his mother were pushed on to tracks in Frankfurt, German police said.
The pair were shoved on to the railway in the city's main station, as a high speed ICE train pulled in.
The mother was able to escape but the boy was hit and run over by the train.
He suffered fatal injuries.
Police said the alleged attacker then tried unsuccessfully to push another person onto the track.
The 40-year-old suspect fled the scene.
He was chased by passers-by and arrested near the station.
Officers said he was being questioned and there was no immediate information on his possible motive.
There appeared to be no connection between the suspect and the victims, a police spokeswoman said.
The boy's mother was taken to a hospital and also was being questioned.
There was no immediate information on her injuries
