German prosecutors say they are investigating three employees of rail company Deutsche Bahn on suspicion of negligent homicide over a train crash last week that killed five people and injured dozens more.
The double-deck regional train that derailed on Friday near the southern Bavarian town of Garmisch-Partenkirchen had about 140 people on board, including students headed home from school for the Whitsun holiday.
A 13-year-old boy and four women aged between 30 and 70 - two of them refugees from Ukraine - were killed in the crash, Bavarian police said.
More than 40 people were injured.
Prosecutors declined to provide details of the investigation, including the reasons why they suspected negligence on the part of the rail workers.