VIENNA (AP) — An Austrian court has found a former fighter for a Syrian rebel group guilty of 20 counts of murder and sentenced him to life in prison.

The court reached the verdict Wednesday after hearing testimony that the man shot and killed at least 20 wounded and defenseless Syrian government soldiers while a member of the Free Syrian Army.

He was charged after a fellow migrant sharing a shelter with the accused reported the man’s story to police last year.

State broadcaster ORF says he denies committing the killings. But law enforcement officials say he confessed to them during questioning.

The defendant isn’t being named in keeping with Austrian confidentiality rules.