Updated

Germany's Interior Ministry says it will "leave no stone unturned" in trying to determine how a Bundeswehr soldier who spoke no Arabic managed to register as a Syrian asylum seeker.

Conceding that mistakes were made, spokesman Tobias Plate said Friday every effort was being made uncover how Franco A. duped authorities and was given a place in a refugee home and collected financial aid.

The 28-year-old lieutenant was arrested Wednesday and charged with preparing an act of violence that he's suspected of planning to blame on refugees.

He allegedly stashed a pistol in a Vienna airport bathroom and was taken into custody when he went to retrieve it in February. He was freed but Austrian authorities informed Germany, and a fingerprint match showed he'd registered as a refugee.