MEXICO CITY — In his final moments, colleagues said, U.S. federal agent Jaime Zapata struggled to fight off his Mexican killers as they attempted to yank him from the armored embassy Suburban he was driving. Zapata and Victor Avila, a fellow Immigration and Customs Enforcement agent, had been forced off the road Tuesday afternoon by two carloads of gunmen as they traveled the busy toll expressway connecting Mexico's heartland to the South Texas border. They hoped to reason with the gunmen - as many as 15 of them in fatigues - who surrounded the vehicle, U.S. officials said. Zapata died trying. He was shot three times. "The agent said, you know, 'We're Americans, we're diplomats,' and the response from the drug cartels was bullets," said U.S. Rep. Michael McCaul, R-Austin, who heads a subcommittee of the House Committee on Homeland Security and was briefed Wednesday on the incident by senior officials in Washington. "They put an AK-47, as I understand it, into the crack in the window and just began to fire away," McCaul recounted. Details of the assault also were provided to the Houston Chronicle by current and former federal agents who reviewed official reports. The attack on U.S. law enforcement officers in the line of duty, in north central San Luis Potosi state some 500 miles south of the border at Laredo, is the first of its kind in Mexico in 26 years. Avila took two bullets to his leg in the attack. Flown to Houston for treatment, he was released from Ben Taub hospital Wednesday. 'He was wonderful' A native of Brownsville, Zapata had joined ICE in 2003 and usually worked out of the agency's Laredo office. He's survived by his family in Brownsville. The 32-year-old graduated from University of Texas-Brownsville with a bachelor's degree in criminal justice and started his law enforcement career with the U.S. Border Patrol in Yuma, Ariz. "He was wonderful," said Cleveland Joyner, whose daughter, Stayce Joyner, had been dating Zapata for more than three years. "I loved the guy." The agents were driving a sport-utility vehicle with diplomatic plates, leading to strong speculation they were targeted because they were U.S. law enforcement officers, though such a move by the gunmen would be bold and reckless, provoking the full wrath of the U.S. government. "I think all hell is going to break loose," predicted one federal agent not authorized to talk on the record. Mexican authorities are leading the investigation. http://www.chron.com/disp/story.mpl/metropolitan/7430922.html Mexican authorities are leading the investigation. in other words they will never be caught.