- German authorities investigating video released by ISIS media group
- ISIS-like flag found in assailant's apartment.
- Attacker was a 17-year-old Afghan man living in Germany, official says
- Police shot and killed attacker; five passengers wounded, two in serious condition
Berlin (CNN)ISIS has claimed responsibility for a brazen attack on a train in southern Germany late Monday evening which left five people wounded, two of them seriously. German authorities are investigating that claim.