A jury in Texas found Jose Guadalupe Diaz Diaz, 43, and Martin Artin Perez Marrufo, 54, guilty of murder, drug trafficking, money laundering, conspiracy to commit racketeering and other crimes back in February.

US prosecutors say the men were part of a hit squad from a gang called Barrio Azteca which on March 13, 2010 shot and killed Leslie Enriquez, an employee of the US consulate in the border town of Juarez, her husband and the husband of another consulate staffer.

The attack came as the trio left a children’s birthday party in Juarez and the shooters mistakenly thought their victims were members of a rival gang, US officials say.

The two men convicted “will now deservedly spend the rest of their lives in prison”, said assistant attorney-general Kenneth Polite, of the justice department’s criminal division.

Mexico had earlier extradited the two suspects.

During the trial US prosecutors presented evidence designed to show that Barrio Azteca is a transnational gang involved in money laundering, drug trafficking and other crimes in El Paso, Texas.

Juarez is a hotspot because it features routes that drug traffickers use to sneak narcotics into the US.