Sabri Çolak (69), an engineering professor who was jailed over alleged links to the Gülen movement, died in prison on Friday morning.

According to a report by online news outlet TR724, Çolak, who was sentenced to seven-and-a-half years’ imprisonment, died of a heart attack while in a high-security prison in Van province. The report said it was known that the professor suffered from heart problems.

Çolak’s body will be returned to his family after an autopsy. The funeral ceremony for Çolak will be held in the Pasinler district of Erzurum province.

TR724 wrote that Prof. Dr. Çolak was detained over alleged links to the Gülen movement in the aftermath of a controversial coup attempt on July 15, 2016. The Erzurum 3rd High Criminal Court had arrested Çolak with an interview in a documentary broadcast on Irmak TV and newspapers with photographs of US-based Turkish Muslim scholar Fethullah Gülen presented as evidence of alleged membership in a “terror organization.”

The same court had also ruled for the continuation of his imprisonment. Çolak was held in prison for over two years.

This article originally appeared on the Stockholm Center for Freedom’s (SCF) website on Aug 24.