The body of the suspect, identified as Zaki Y. M. Hasan was found hanging from the bathroom door in his cell at 10.22 a.m. local time (0722GMT) on Sunday, a statement issued by the Istanbul’s Chief Public Prosecutor’s Office said.
The suspects were arrested earlier this month as part of a probe by Istanbul prosecutors of alleged spying by the Gulf state.
The AFP reported that the man was detained as part of Turkey’s probe into the murder of Saudi journalist Jamal Khashoggi last October.
But Anadolu Agency said the deceased and one other were remanded in custody on charges of political, military and international espionage.
Reuters reported that the two suspects were arrested on April 19 and confessed to spying on Arab nationals, a senior Turkish official said at the time. Turkey was investigating whether the arrival in the country of one of them was related to the murder of Saudi journalist Jamal Khashoggi.
One of the two men arrived in Turkey in October 2018, days after Khashoggi was murdered inside Saudi Arabia’s consulate in Istanbul, the official said at the time of their detention, adding the other had arrived later to help his colleague with the workload.
Khashoggi, a Washington Post columnist and critic of Saudi Crown Prince Mohammed bin Salman, was killed in the consulate on Oct. 2 by a team of Saudi operatives, provoking an international outcry.