This is not the first time armed groups in Syria have killed citizens for supporting the government.
In December, a video apparently showed armed men killing an unarmed civilian execution style.
Separately, militants were captured on a video using anti-aircraft fire to shoot at what appears to be a passenger plane.
The militants of the so-called Free Syrian Army have also posted two other troubling videos on the internet. They show militants testing chemical weapons on lab rabbits and threatening to use chemical weapons to massacre Alawite Shias and Assad supporters.
The Syria crisis began in March 2011, and many people, including large numbers of army and security personnel, have been killed.
The Syrian government says that the chaos is being orchestrated from outside the country, and there are reports that a very large number of the insurgents are foreign nationals.
Damascus says the West and its regional allies Qatar, Saudi Arabia, and Turkey are supporting the armed groups.
In addition, several international human rights organizations have accused the militants fighting the Syrian government of committing war crimes.