German prosecutors seek motive in fatal train pushing German prosecutors are still trying to determine the motives of a man suspected of pushing an 8-year-old boy and his mother in front of a train at Frankfurt's main station

BERLIN -- German authorities are still trying to determine the motive of a man suspected of pushing an 8-year-old boy and his mother in front of a train at Frankfurt's main station, killing the boy, and will assess whether he is mentally ill, prosecutors said Tuesday.

The suspect, a 40-year-old Eritrean citizen who lived in neighboring Switzerland, hasn't yet given any information on a possible motive, said Nadja Niesen, a spokeswoman for prosecutors in Frankfurt.

The mother and then the boy were pushed onto the tracks as a high-speed ICE train was pulling into the Frankfurt station, one of Germany's busiest, on Monday morning. The 40-year-old mother managed to escape by getting out of the train's way, but the boy was run over by the train and suffered fatal injuries.

The suspect then apparently tried unsuccessfully to push a third victim, a 78-year-old woman, onto the track before fleeing the scene. She suffered a shoulder injury.

The man, whose name has not been released, was chased by passers-by, including an off-duty police officer, and arrested near the station.

He will be brought before a judge Tuesday to determine whether he can be kept in custody pending possible charges of murder and attempted murder, Niesen said. She added that the nature of the crime raises the possibility of mental illness and a psychiatric assessment will be conducted as part of the investigation.

Niesen said investigators are looking at all possibilities but there was no indication of any connection to an incident last week in which an Eritrean man was seriously injured in a drive-by shooting near Frankfurt that authorities believe was racially motivated.

The suspect, believed to be a father of three who has lived in Switzerland since 2006, told investigators that he took a train to Frankfurt from the Swiss city of Basel a few days ago.

Interior Minister Horst Seehofer planned to meet the heads of German security authorities in Berlin later Tuesday following the incident.