The bodies of two anti-ISIS activists, 22-year-old Ibrahim Abdel Qader and 20-year-old Fares Hammadi, were found Friday in an apartment in the Turkish town of Sanliurfa. Both men were beheaded.
The deaths of the two young Syrians, both members of a citizen-journalist group called "Raqqa Is Being Slaughtered Silently," sent shockwaves through the exile Syrian community in Turkey, NBC News reported.
Ibrahim's brother, Ahmed, told NBC News an acquaintance of theirs from Raqqa, Tlas Surur, who arrived in Sanliurfa about a month and a half ago, killed both men. Surur claimed he had defected from ISIS and wanted to help the movement against them.
A Turkish police source told NBC News that evidence links Surur to the killings.
Ibrahim's brother believes that Surur managed to slip back to Syria and rejoined ISIS. But he hasn't remained silent. During the interview with NBC News Ahmed received what he said was a threatening text message from Surur.
