Oversight Committee Chairman Darrell Issa and Ranking Member on the Senate Judiciary Committee Senator Charles Grassley sent a letter to Inspector General Michael Horowitz asking for an investigation into the murder of ICE Agent Jaime Zapata.

Members of the Zeta drug cartel murdered agent Zapata in Mexico on February 15, 2011. Otilio Osorio in Dallas, TX purchased the gun used to murder Agent Zapata and injure his partner Agent Victor Avila. The serial number was removed and the gun was smuggled into Mexico. Mr. Osorio was a known straw purchaser months before he acquired the gun. ATF didn’t arrest Mr. Osorio until after Agent Zapata’s death. A second gun used in the murder was trafficked by Manuel Barba, another suspect under ATF surveillance.

Mr. Horowitz finished his investigation on Fast & Furious last week, and he mentioned a March 4, 2011 letter Senator Grassley sent to then ATF Director Kenneth Melson about Agent Zapata’s murder. The letter, sent back on March 8, 2011, answered none of Senator Grassley’s questions.

ATF had a few opportunities to arrest two traffickers before they bought the gun that was used to murder Agent Zapata. Senator Grassley and Chairman Issa want answers to those questions.

“As outlined in those letters, it appears the ATF had probable cause to arrest Otilio and Ranferi Osorio on November 9, 2010, when ATF witnessed the Osorio brothers providing 40 weapons with obliterated serial numbers to an undercover ATF informant in a Walmart parking lot for the purpose of trafficking the weapons to Mexico,” they wrote to Mr. Horowitz. “The controlled delivery was initiated as part of an investigation by the DEA, which tipped ATF off to the transfer. Right after the drop-off, the Osorio brothers met with their next-door neighbor Kelvin Morrison, who entered their vehicle and was identified later that day when police stopped the car.”

ATF also knew Ranferi Osorio and Kelvin Morrison were buying weapons and transferring them to Mexico in September 2010. Yet, they weren’t arrested until after Agent Zapata was murdered.

Drug cartel members murdered Border Patrol Agent Brian Terry on December 14, 2010. They used guns from Operation Fast & Furious. Agent Terry’s murder and Fast & Furious have been largely ignored by the media and the administration, but Agent Zapata has received even less attention. The government has given very little information about Agent Zapata.