Fast and Furious scandal: Suspected triggerman in border agent's murder arrested

The cartel member suspected of shooting and killing U.S. Border Patrol agent Brian Terry in 2010 with a gun supplied by the U.S. government was arrested in Mexico Wednesday, senior law enforcement, Border Patrol, and congressional sources told Fox News.

The suspect, Heraclio Osorio-Arellanes, was apprehended by a joint U.S.-Mexico law enforcement task force that included the Drug Enforcement Administration, U.S. Marshals and the Border Patrol Tactical Unit (BORTAC).

A $250,000 reward had been sought for information leading to the arrest of Osorio-Arellanes, who was captured at a ranch on the border of the Mexican states of Sinaloa and Chihuahua. U.S. authorities have said they will seek his extradition.

Terry was killed on Dec. 14, 2010 in a gunfight between Border Patrol agents and members of a five-man cartel "rip crew," which regularly patrolled the desert along the U.S.-Mexico border looking for drug dealers to rob.

The agent's death exposed Operation Fast and Furious, a Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) operation in which the federal government allowed criminals to buy guns in Phoenix-area shops with the intention of tracking them once they made their way into Mexico. But the agency lost track of more than 1,400 of the 2,000 guns they allowed smugglers to buy. Two of those guns were found at the scene of Terry's killing.