In February 2011, Immigration and Customs Enforcement (ICE) special agent Jaime J. Zapata was shot and killed on a highway in Mexico by members of the Los Zetas drug gang. It was the first time an ICE agent had been killed in Mexico since 1985. Two of the men accused of carrying out the attack are now on trial in the U.S. and today the Washington Post has the dramatic story of what happened the day agent Zapata was killed.

The members of the drug gang, in two large vehicles, were not looking to kill U.S. agents, they claim. They had standing orders to steal cars that could be useful to the gang. The attack was an attempt at carjacking.

Two ICE agents, Zapata and his partner Victor Avila were driving an armored SUV down a Mexico highway when they came under attack. They tried to explain they were diplomatic agents but the attackers apparently didn’t understand. The armored car the agents were riding in had been hardened to withstand bullets and even grenades. It should have kept the agents safe if not for a completely unexpected turn of events:

What happened when the agents’ $160,000 armored Suburban was brought to a halt — blocked by the hit squads — was stunning.

The SUV was built to withstand high-velocity gunfire, grenades and land mines. Yet it also came with a consumer convenience: when put in park, its doors unlocked automatically, a flaw previously unaddressed by the U.S. Bureau of Diplomatic Security worldwide.

When [hit squad member Julian Zapata] Espinoza yanked the handle, the heavy driver’s side door creaked open.

“I think we were all surprised,” the surviving agent, Avila, testified as he spoke publicly for the first time about the assault.

The shock all around gave Zapata time to pull shut his door. But surrounded at gunpoint, confused and perhaps fumbling to relock the doors, Avila testified, the bulletproof window near him somehow lowered two inches.

The gang members stuck two guns in the open window and demanded the agents open the doors. When they refused, the gang members fired and agents Zapata was struck in the chest. Agent Avila pushed the barrel of the guns out and closed the window. He radioed for help: “This is Victor Avila from ICE! We are shot! We are shot!” Eventually, Avila pushed Zapata’s leg on the accelerator and they smashed through one of the cars that had blocked them in. They didn’t go far as Avila was still in the passenger seat, but the gang members gave up.

Both families have sued the federal government for $75 million dollars. So far a federal judge has not allowed their lawsuit to proceed saying they lack sufficient evidence of wrongdoing. The families want to know why the agents were sent out unescorted on a highway where drug gangs were known to operate.

From the testimony of what happened that day, it sounds as if the agents could have survived if not for the oversight of the Diplomatic Services regarding the automatic unlocking of the doors. It’s incredible that no one had identified this flaw in the armored vehicle’s security before.