An Oklahoma sheriff's agency where a reserve deputy fatally shot an unarmed man has found what it calls deficiencies in files of about 50 of its 128 reserve ranks, though the bulk are considered clerical in nature, a spokesman said Thursday.

Tulsa County Sheriff's Office reserve coordinator Justin Green said many of the faults were minor, such as outdated driver's licenses or missing training certificates.

"Some just needed to come in and get a picture for our records-keeping system," the deputy said. "Most of it was clerical, pretty nominal paperwork kind of stuff."

Green declined to release the internal audit's findings, saying it was considered an ongoing investigation. He said the agency has set a Tuesday deadline for reserve deputies to come in and correct the so-called deficiencies. Green said he had no estimate when an outside review of the program would be finished, or when the volunteer deputies would be reactivated.

The program was suspended after volunteer deputy Robert Bates fatally shot a man in April. Bates, who left the agency, says he confused his handgun for a stun gun and has pleaded not guilty to second-degree manslaughter.

A grand jury is also meeting in Tulsa for a sixth week as it investigates allegations of wrongdoing in the agency.

Thousands of residents petitioned for a probe of the sheriff's office after Bates fatally shot Eric Harris in a Tulsa street during a sting involving gun sales. The petition calling for the investigation gained momentum among citizens with the release of a leaked 2009 memo that questioned Bates' competency.

Bates is a close friend of Sheriff Stanley Glanz and had previously donated thousands of dollars in cash and equipment to the agency, raising questions about the reserve deputy program and whether Bates and others received special treatment in return for the gifts.

A spokeswoman for the Harris family attorney, who had released the 2009 memo and called for a thorough review of the reserve program after he shooting, did not immediately return a message seeking comment Thursday on the internal audit's findings.