New incriminating reports have surfaced about the Oklahoma reserve deputy who shot an unarmed black man in Tulsa County earlier this month.

Video of the incident shows the victim, 44-year-old Eric Harris, running away during a sting operation on April 2. Eventually, authorities catch up to Harris and tackle him to the ground. Moments later a shot is fired, and Reserve Tulsa County Deputy Robert Gates can be heard on the tape apologizing for releasing a shot from his handgun, as opposed to using a Taser to compose him.

"Taser! Taser!" says the 73-year-old white reserve sheriff's deputy before pulling the trigger.

"Oh, I'm sorry. I shot him," says the former policeman.

According to The Associated Press, Harris was then treated by medics at the scene and died at a local hospital.

Following the shooting, investigations suggested that Tulsa County sheriff's office tried to cover up the fact that the volunteer deputy had not received proper training.

"New information has been submitted to this office regarding actions in the Sheriff's Office that are worthy of further investigation beyond the scope of the manslaughter case," a statement from Tulsa County District Attorney Stephen Kunzweiler's office said Friday, according to NBC News.

"I am highly concerned about recent allegations that have surfaced and I have been in contact with independent law enforcement agencies regarding further investigation into these matters," Kunzweiler said in the statement.

A 2009 Tulsa County Sheriff's Department report obtained by NBC News found that Bates wasn't required to follow some protocols of the department.

The report also found that department employees were asked by the department's captain, Tom Huckeby, and the chief deputy, Tim Albin, to modify reviews and training hours documentation for Bates.

Meanwhile, those who raised concerns about Bates' skill and the violations were told to keep their mouths shut by Albin, the review found.

Meredith Baker, general counsel for the sheriff's office, said Friday, "We intend to fully cooperate with any legal investigation."