Gun buyer linked to federal agent's murder to plead guilty

A Dallas County man linked to the murder of ICE Agent Jaime Zapata agreed to plead guilty to weapons violations.

Otilio Osorio, 22, of Lancaster, Texas, agreed to plead guilty in federal court to three counts of a 21-count indictment against him.

Prosecutors say one of three guns found at the scene in Mexico where Agent Zapata was shot to death on February 15 was traced back to Osorio. Investigators believe he was the straw purchaser of the weapon, bought in Texas four months before the murder. As part of an agreement with the U.S. Attorney's Office, Osorio agreed to plead guilty to conspiracy to make a false statement in firearms records and possessing a weapons with a removed serial number.

Seven other defendants in the case are also expected to enter guilty pleas. The maximum penalty for each count is five years in prison and a $250,000 fine. Sentencing dates have not yet been scheduled.

As reported by CBS News, Congressional Republicans investigating allegations that the Obama administration allowed thousands of weapons to be trafficked into Mexico have asked for more information about the circumstances surrounding Agent Zapata's death.

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On Wednesday, Rep. Darrell Issa and Senator Charles Grassley wrote a letter to Attorney General Eric Holder, questioning how the government handled the investigation of Otilio, his brother Ranferi Osorio and another defendant Kelvin Leon Morrison.

According to a joint statement from the offices of Rep. Issa and Sen. Grassley, "the three straw purchasers were known to the Bureau of Alcohol, Tobacco, Firearms and Explosives, or ATF, long before one of the guns purchased by the brothers was linked to the murder of Agent Zapata."

Records obtained by CBS News show ATF watched as the Osorio brothers and Morrison transferred weapons to a confidential informant on November 9, 2010, but failed to arrest the men. The agency's report documenting that incident was dated February 25th, the same day ATF reportedly received a record tracing the Zapata crime scene gun to Otilio.

The Attorney General has denied knowing that gunwalking was part of an ATF operation that allowed weapons to be smuggled into Mexico. The Justice Department Inspector General has launched an investigation.