In this post I want to collect links about the role of Muslim radicals among the rebels. As some other posts in this blog it is a post that will be updated regularly with new information.
Syria Rebel: Sunni Jihadists After Shiite Hostages: A Syrian rebel commander holding 10 Lebanese Shiites hostage said Thursday he is willing to release the men but fears doing so could set off a wave of reprisal attacks by Sunni extremists. [..] He said the kidnappings were aimed at persuading Hezbollah, a strident backer of President Bashar Assad, to reconsider its commitment to the Syrian regime. Instead it set off a string of revenge kidnappings by Shiite clansmen inside Lebanon, with two Turks and some 20 Syrians being snatched by gunmen. [..] "After (Omar's) release, the Northern Storm brigade began to receive threats from Sunni extremist groups in Lebanon, Iraq and some in Syria," Abu Ibrahim told The Associated Press in an interview at a customs house in this Syrian border town: "They told us, the hostages are members of Hezbollah and should be killed."
A field guide to Syria's jihadi groups by Aron Lund provides a description of the main fighting groups in Syria.