LAREDO, Texas – A teenager accused of being a hit man for a drug cartel pleaded guilty to felony murder Thursday, abruptly ending a trial that exposed the cartel’s workings in the U.S. and Mexico.

Rosalio “Bart” Reta, 17, was immediately sentenced to 40 years in prison. He still faces separate charges in another killing in Laredo that was allegedly carried out on the orders of the Mexican Gulf Cartel.

Witnesses testified Wednesday that Reta and two other men working for the cartel were paid $15,000 to kill a Laredo man in January 2006. Phone records linked the hit men, the ring leader and suppliers of the guns and car used in the shooting, Detective Robert Garcia testified.

Prosecutors say the shooting victim, Noe Flores, was the half brother of the intended target. Flores was shot at least seven times.

One other defendant has pleaded guilty in the case. The alleged ring leader, Jesus “Jesse” Gonzales, fled to Mexico.

Authorities say Reta worked on both sides of the border for Miguel Trevino Morales, the leader of the cartel’s operation in Nuevo Laredo, Mexico. He was allegedly part of a “cell” of young enforcers that followed rivals and tracked members of the cartel’s own ranks.

Reta, a U.S. citizen, was extradited last year from Mexico to face charges in Flores’s death. Authorities said he requested extradition after being arrested in connection with an explosion that killed four people in a crowded bar in Monterrey, Mexico.

Emanuel Arriaga, a spokesman for the Nuevo Leon state Attorney General’s office, said Wednesday that prosecutors in Monterrey couldn’t link Reta to any killings.

A service of the Associated Press(AP)