A Mexican man was convicted of first-degree murder Tuesday for the 2010 killing of Border Patrol agent Brian Terry.

The group of bandits were heavily armed when they encountered Terry's tactical operations unit in a wash near Peck Canyon, just outside Nogales, Arizona.

They carried at least five AK-47 and AR-15 rifles, 180 rounds of ammunition and enough gear to survive for several days in the desert. They were looking for marijuana smugglers to rob and weren't expecting federal agents. A gunfight ensued; the 40 year old Terry was struck. "Willie, I'm hit, I can't feel my legs," Terry called out.

A round had severed his spinal cord. He died that night.

Heraclio Osorio Arellanes was convicted on nine separate counts, including first degree murder. He is one of seven defendants charged in Terry's murder. Most have been convicted and sentenced to either life in prison or about 30-year-long sentences.

How the bandits came upon some of the weapons found at the crime scene was never discussed in the government's prosecution of the case. Two of the rifles found originated from a Bureau of Alcohol, Tobacco and Firearms operation in Arizona dubbed Operation Fast and Furious. The objective was to allow guns to be sold to cross-border smugglers in hopes they would turn up in the hands of higher level members of Mexico's cartels. Instead, ATF lost track of nearly 2,000 of the weapons. They were found at crime scenes in Ciudád Juárez, in Sonora, Arizona, and even years later, at the hideout of Sinaloan drug kingpin Joaquín El Chapo Guzmán. 

But a judge ordered that details of the government scheme were not to be used in either the murder cases nor in the widely publicized month long trial of Guzmán.