One of the Muslim gunmen killed in May during an attack on attendees of a "Draw Mohammad" cartoon contest in Garland, Texas, legally purchased his handgun five years ago from a Phoenix gun shop involved in the botched federal firearm operation known as Operation Fast and Furious.

Nadir Soofi attempted to purchase a gun from the Lone Wold Trading Co. in 2010, but drug and assault charges on his record resulted in federal authorities flagging and placing a seven-day hold on his purchase, reported the LA Times.

Unbeknown to Soofi, the Lone Wolf Trading Co. was at the center of a federal sting operation known as Fast and Furious involving the sale of illegal firearms to Mexican drug lords and gun traffickers.

The idea of the program, led by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), was to deliberately allow gun stores to sell thousands of illegal weapons, including AK-47s and .50-caliber rifles, to criminals and then attempt to track those guns as they made their way back to large gun smuggling networks and Mexican drug cartels.

However, the Obama administration did not coordinate with the Mexican government and failed to track the weapons, resulting in the loss of an estimated 1,400 guns, some of which were linked to the 2010 killing of U.S. Border Patrol Agent Brian Terry in Arizona, as well as shootings in Mexico, according to The Daily Caller.

Only 24 hours after the seven-day hold was placed on Soofi, federal authorities inexplicably lifted the hold and allowed Soofi to walk out of the store with a 9 mm pistol, according to the Times.

"In other words," says Town Hall, "ATF and the FBI pushed through a shady gun sale that ultimately was used in a terror attack against Americans on U.S. soil."

A day after Soofi used that gun in his attack on the cartoon contest in Garland, the Justice Department sent an "urgent firearms disposition request" to Lone Wolf seeking more information about the gun, though it did not specify whether the gun was used in the attack, according to a June 1 letter from Sen. Ron Johnson, R-Wis., chairman of the Senate Homeland Security Committee, to Attorney General Loretta Lynch, reports the Times.

The FBI has reportedly refused to release details, including serial numbers, about the weapons used by Soofi and his roommate Elton Simpson during the attack. Now "Senate investigators are pressing law enforcement agencies for answers, raising the chilling possibility that a gun sold during the botched Fast and Furious operation ended up being used in a terrorist attack against Americans," says the Times.

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Among other things, Johnson is demanding to know whether federal authorities have recovered the gun Soofi bought in 2010, where it was recovered and whether it had been discharged, according to the letter. He also demanded an explanation about why the initial seven-day hold was placed on the 2010 pistol purchase and why it was lifted after 24 hours.

Asked recently for an update on the Garland shooting, FBI Director James B. Comey earlier this month declined to comment. "We're still sorting that out," he said.

Officials at the Justice Department and the FBI declined to answer questions about whether the 9-millimeter pistol was one of the guns used in the Garland attack or seized at Soofi's apartment.

It remains unclear whether Soofi's 2010 visit to Lone Wolf is a bizarre coincidence or a missed opportunity for federal agents to put Soofi on their radar years before his contacts with Islamic extremists brought him to their attention."