A key backer of Syria's White Helmets search and rescue group has been found dead near his home in Istanbul.
James Le Mesurier was the founder of Mayday Rescue, which provides training to White Helmets first responders.
The outfit is famous for rushing into air strikes in Syria to pull out the wounded.
How the former British army officer died in Turkey is not yet known.
One security source said he appears to have fallen from his balcony and was being treated as a suicide.
A separate diplomatic source said the cause was unclear.
Le Mesurier's non-profit received funding from the United Nations and several world governments.
The White Helmets, which are formally known as the Syria Civil Defense group, are officially neutral in the war and heralded by Western countries.
But it's reviled by the government in Damascus, which views the White Helmets as aiding the various rebel groups in the country.
It does operate mostly in rebel territory.
Video aired on Syrian television over the weekend is said to show government troops firing on Turkish forces near the border.
Also in the Syrian war on Monday (November 11), Turkey's President Tayyip Erdogan is following through on a promise to start deporting captured Islamic State fighters back to their home countries -- mostly in Europe and the Untied States.
Turkish media is reporting that an American jihadist and a German have been expelled and will follow with more.
They eventually plan to get rid of about 2,500 militants.
Many were previously held by Kurdish forces before the Turkish offensive forced the Kurds out.
It's not yet clear where the prisoners are being transported or how the Western countries are reacting.
Several have previously refused to take back the militants, and have even revoked their citizenship.