Washington (AFP) – Two Mexican members of a hit squad for the notorious Los Zetas drug cartel were given life prison sentences Monday for the 2011 murder of a US immigration agent inside Mexico.

The US Justice department said that Jose Emanuel Garcia Sota, 36, of San Luis Potosi, Mexico, and Jesus Ivan Quezada Pina, 29, of Matamoros, Mexico, shot dead Immigration and Customs Enforcement special agent Jaime Zapata in a car-jacking on a busy highway near San Luis Potosi, 260 miles (420 kilometers) north of Mexico City.

They wounded another ICE special agent, Victor Avila, in the ambush.

It was the first killing of a US federal agent on Mexican soil in 26 years and sparked a huge investigation by law enforcement from both countries.

The case raised questions over whether the Mexican drug gang had deliberately targeted the two Americans, or whether the agents were simply caught up in commonplace cartel violence.

A total of seven men were extradited from Mexico to the United States to stand trial over the murder.

Garcia and Quezada were convicted in a jury trial on July 27, and both received two life terms in prison Monday in the first sentences handed out in the case.

The five others, all of whom pleaded guilty to murder and murder-related charges, are to be sentenced on Tuesday.

The two ICE agents were driving toward Mexico City on February 15, 2011 in an armored Chevrolet Suburban with diplomatic license plates when they were attacked.

The car was blasted by multiple assault rifles; investigators later found some 90 shell casings at the scene.

“While working on behalf of our country, they were ruthlessly gunned down in a carjacking attempt by members of hit squads for the Los Zetas drug cartel,” said US Attorney Jessie Liu.

“We have never forgotten what happened to these two American heroes in that ambush on a Mexican highway more than six years ago.”