VietJoy

A police officer stands watch after the body of James Le Mesurier, a former British army officer who helped found the White Helmets volunteer organization in Syria, was found in Istanbul, Turkey, Nov. 11, 2019.

A key backer of the Syrian White Helmets rescue organization was found dead Monday near his home in Istanbul, according to Turkish authorities.

James Le Mesurier, a former British army officer, was the founder of Mayday Rescue, which trained the White Helmets, formally known as the Syrian Civil Defense group. The group is known for rescuing people wounded after airstrikes in opposition-controlled parts of Syria. It is credited with saving tens of thousands of lives during the conflict.

Le Mesurier was found near his home with fractures to his head and legs, according to Turkish media reports. An investigation has been launched into his death.

The White Helmets expressed its "deepest sorrow and solidarity with his family" on Twitter Monday.

The Syrian government, as well as its Russian and Iranian allies, have accused the White Helmets of aiding terrorists.