House Oversight Committee Chairman Jason Chaffetz issued subpoenas Thursday to two ATF agents after they failed to show at a hearing examining the 2011 murder of Immigration and Customs Enforcement (ICE) agent Jaime Zapata.

“I'm tired of hearing from just [Justice Department] management, I want to hear from the people that actually are on the front lines doing this,” Chaffetz, R-Utah, said.

The committee will now seek to compel testimony from William Temple, special agent in charge of the Dallas Field Division, and Ronald Turk, associate deputy director of the Bureau of Alcohol, Tobacco, Firearms and Explosives, later this month.

The hearing Thursday was meant to examine alleged lapses in the ATF's investigation into the trafficking of guns later used in the February attack that killed Zapata and wounded his ICE colleague, Special Agent Victor Avila.

An inspector general report was completed more than five years after the committee and Sen. Charles Grassley, chairman of the Senate Judiciary Committee, inquired into Zapata’s murder. Zapata was killed by members of the Los Zetas drug cartel while on official business in Santa Maria del Rio, Mexico.

ATF Acting Director Thomas Brandon said Thursday he did not order Temple and Turk to skip the hearing -- but agreed with their decision not to appear, which drew a bipartisan rebuke from Chaffetz and ranking Democrat Elijah Cummings.

“That puts us in a kind of awkward position. We got the boss, 'OK guys, you don't have to show up.' And that sends a hell of a message. That's a problem,” the Maryland Democrat said.

Chaffetz complained ATF “continues to insist” the committee should not speak with Turk and Temple.

Another invited witness, John Craft, a prosecutor in the Office of the U.S. Attorney for the Eastern District of Texas, did not appear. But the chairman said due to the lateness of their invitation, he would not receive a subpoena.

Questions about the firearms used to kill Zapata surfaced during the separate congressional probe of Operation Fast and Furious and the death of Border Patrol agent Brian Terry.

The IG issued its Operation Fast and Furious report in 2012, but did not issue its report on the Zapata case until March 1.

According to the report, two weapons used in Zapata's murder were traced back to Otilio Osorio, who bought his gun at a Dallas gun show, and Robert Riendfliesh, who purchased a gun at a pawn shop in Beaumont, Texas.

The IG said the ATF were aware in 2010 that Osorio and his brother might be trafficking firearms to Mexico, but they did not follow up or further investigate until after Zapata’s death.

Otilio Osorio and Riendfliesh were arrested in late February 2011 after the ATF confirmed weapons used in Zapata's murder had been purchased by them.

The report faulted ATF for its handling of the case, saying there was "probable cause" to arrest Osorio and his brother "after ATF witnessed the Osorios complete a transfer of 40 firearms on November 9, 2010."

The IG said: “Overall, we found numerous problems with ATF’s assimilation of information concerning [the suspects] ... and the timeliness of ATF’s response to mounting evidence that they were committing firearms offenses.”

Last week, Chaffetz and Grassley sent a letter demanding Justice explain the reason the investigation has dragged on.

"It has been nearly five years since the probe was requested. Given the high level of congressional interest in this matter and the seriousness of the allegations, we are perplexed that your investigative work took so long,” they wrote.

Judiciary Committee Press Secretary Taylor Foy told Fox News that the panel is interested in part in “whether government employees involved in the debacle were held accountable.”

Editor’s Note: An earlier version of this report incorrectly attributed a comment to DOJ Inspector General Michael Horowitz and incorrectly described an exchange between him and Chaffetz.