German police arrested a 16-year-old Afghan youth on Sunday on suspicion of a connection to the killing of nine people by an 18-year-old gunman in Munich, authorities said.

The youth was under investigation for possibly having failed to report the plans of the gunman, who later shot himself, a police statement said.

“There is a suspicion that the 16-year-old is a possible tacit accomplice to (Friday’s) attack,” it said. Police earlier said the gunman was a deranged Iranian-German who was fixated with mass killings but not inspired by Islamist militancy.

The Afghan youth was questioned after he contacted police following the shooting on Friday, the statement said. Investigators later uncovered contradictions in his statements, it said, without providing any further details.