"Intelligence services arrested Ali Kayali, also known as Mihrac Ural and the main suspect in the 2013 Banias massacre, as he tried to flee across the border," Syria's official news agency Sana reported.
It is unclear which country he was trying to flee to.
In May 2013, government forces and forces loyal to the regime killed at least 248 people in mass executions in the predominantly Sunni Muslim town of Banias and the nearby village of al-Bayda, according to Human Rights Watch (HRW).
The human rights organization has previously described the incident as one of the deadliest mass executions during the country's bloody conflict.
