translator: there are seven tactical vehicles and three houses. and god willing, we ll be attacking this checkpoint. reporter: this specific one, i ask. translator: yes. this specific unit did a lot of killing. reporter: this is what turned ahmed against the government. a peaceful protest last may. ahmed was in it when government soldiers opened fire, gunning them down. [ gunfire ] ahmed and other sources say up to 40 people were killed as army troops continued to fire into the scattering crowds of protesters. translator: we were stunned. some people stood still. some people fell dead. we expected something like tear gas, but we never expected this kind of killing. reporter: ali and ahmed want to make sure that never happens again. translator: once the weapons are in the hands of the people,