Federal agents have arrested a convicted felon for allegedly providing the gun later used to kill ex-NFL quarterback Steve McNair, The Associated Press learned today.

WASHINGTON — Federal agents have arrested a convicted felon for allegedly providing the gun later used to kill ex-NFL quarterback Steve McNair, The Associated Press learned today.

Two law enforcement officials, speaking on condition of anonymity because they were not authorized to discuss the case, said the suspect was arrested by Bureau of Alcohol, Tobacco, Firearms, and Explosives agents.

Federal prosecutors in Nashville planned to announce the charges at a press conference later today.

McNair was shot to death on July 4 at his condo by his 20-year-old mistress Sahel Kazemi, who then turned the gun on herself. Police have said Kazemi bought the gun in a private sale from a person they haven't identified.

Police announced in a news conference last week that Kazemi purchased "a fully loaded nine millimeter pistol from a private individual" who met her in the parking lot of the mall where she worked at a Dave & Busters restaurant.

Kazemi met the person when she was trying to sell her car. She mentioned to him that she was looking to buy a gun and he told her he had one for sale, police said. The sale took place two days before McNair's shooting.

Authorities believe McNair was asleep when Kazemi put the pistol to his head and pulled the trigger. She put two more slugs into his chest and a fourth bullet into the other side of his head before shooting herself.

McNair, a married father of four, walked away from the NFL last year. "Air McNair" was known as a gutsy quarterback who played through serious injuries and led his Tennessee Titans to a Super Bowl.

Though the gun sale in question did not involve a licensed gun dealer, the ATF recently warned all gun dealers in Tennessee that they must still comply with federal gun laws despite a new state law aimed at easing such requirements for weapons manufactured and sold in-state.