Germany's top security official says the country's investigation so far into an attack on passengers aboard a regional train in Bavaria indicates the suspect acted alone.

Interior Minister Thomas de Maiziere told reporters in Berlin on Wednesday it appears that the 17-year-old Afghan asylum-seeker, who was shot and killed by police after wounding five in the ax and knife attack, was radicalized by watching online propaganda.

De Maiziere says a video of the suspect that was posted by the Islamic State group is authentic, and seems to be a "classic farewell video of a suicide attacker."
He says it's not yet clear when the video was shot.