ISTANBUL (AP) — A former British army officer who helped found the White Helmets volunteer organization in Syria, was found dead in Istanbul early Monday, Turkish officials said.

James Le Mesurier's body was found near his home in the Beyoglu district by worshippers on their way to a mosque, the state-run Anadolu news agency reported.

The Istanbul governor's office said that "comprehensive administrative and judicial investigations into Le Mesurier's death have been initiated."

Anadolu said police established that no one had entered or left his home at the time of the incident, and believe he may have fallen to his death.

Le Mesurier was the founder and CEO of May Day Rescue, which founded and trained the White Helmets also known as the Syria Civil Defense.

The private DHA news agency said authorities were investigating whether he had committed suicide, saying he had allegedly been on anti-depressant pills. Anadolu also reported that Le Mesurier's wife told police her husband had been taking medicine to treat "intense stress."

It said Le Mesurier's body was awaiting an autopsy.