BERLIN (AP) — German officials say a Syrian man being held on suspicion of fighting for an extremist group in his homeland has hanged himself in a Hamburg jail cell.

Hamburg’s state justice ministry said the body of the 40-year-old, identified only as Abdullah K. in line with German privacy rules, was found in his cell during a routine check on Wednesday morning. It said an autopsy is being conducted.

Prison authorities had previously detected no signs of “suicidal behavior” and said the suspect had appeared “stable” during a conversation with psychologists last week.

The man was arrested in June along with three brothers. They were accused of membership in a terrorist organization for fighting for the Nusra Front in the northern Syrian city of Ras al-Ayn starting in late 2012.