The FBI cleared an Oklahoma sheriff’s deputy of violating a suspect’s civil rights in the case of a Tulsa County reserve deputy fatally shooting an unarmed man after the volunteer grabbed his revolver instead of his stun gun, the sheriff said Monday.

But it remains unclear if 73-year-old Robert Bates was qualified to use the gun he fired April 2, killing 44-year-old Eric Harris, said Sheriff Stanley Glanz.

Bates, a wealthy insurance executive who has known Glanz for 25 years on both a professional and personal level, faces a second-degree manslaughter charge for accidentally killing Harris during a gun-and-drug buy sting. A report by the Tulsa World found that supervisors falsified training records for Bates, a deep-pocketed donor who has supplied the department with cars and electronic equipment during his seven years as a volunteer reserve deputy.

Glanz, who received a $2,500 donation from Bates during his 2012 reelection campaign for sheriff, said his friend was properly trained.

“Mr. Bates has been to the range several times and is qualified, and that is documented,” the sheriff said at a news conference Monday. But asked specifically about Bates’ training with the revolver used in the killing, Glanz added: “That is something we’re still looking at and it will be part of the administrative review.”

Bates was in a support role April 2 as nine members of a department Violent Crimes Task Force carried out the sting on Harris. The suspect ran from an undercover’s truck following the exchange of a gun for money, but officers were to run Harris down and tackle him to the ground.

Two officers had Harris pinned to the ground when Bates yelled, “Taser, Taser!” and fired his gun instead of the stun gun.

The officers wrestling with Harris say they had no idea he had been shot, even after Harris apologized for it and Harris said he couldn’t breathe because he’d been shot.

“F--k your breath,” one deputy, identified as Joseph Byars, can be heard saying on body camera video.

Byars and Deputy Michael Huckeby have received threats for their respectives roles in the incident, Glanz said, according to the Tulsa World.

"The deputies have been reassigned for their safety," Glanz said.

Both the violent crimes and drug task forces have been shut down by the agency during an administrative review of the incident, officials said.

Glanz apologized for what happened and offered his condolences to the victim’s family. Bates, in an appearance Friday morning on the “Today” show, also apologized and reiterated his claim that the shooting was a mistake.

"Lives and deaths occur every day in law enforcement. It affects everyone in this community; it affects the agency," Glanz said Monday, according to the World. "I'm sorry we were all involved, and my sympathy goes out to that family.”