Activists push for grand jury to investigate Tulsa County Sheriff's office
Tulsa County reserve sheriff's deputy Robert Bates appears on NBC's 'Today Show' on April 17, 2015.

An Oklahoma activist group submitted a petition on Friday aimed at compelling a grand jury investigation into the Tulsa County Sheriff's Office, under scrutiny since a white part-time sheriff's deputy fatally shot a black suspect in April.

The petition containing 8,800 signatures was submitted to the Tulsa County Clerk's Office by a group called "We the People Oklahoma" and accuses the sheriff's department of violating its duty to preserve the peace and uphold the law.

Robert Bates (pictured above), a 73-year-old volunteer reserve deputy, has been charged with manslaughter in the April 2 death of Eric Harris in a police sting operation. The sheriff's office says Bates thought he was using a Taser instead of a gun when he shot Harris.

The petition calls for a grand jury probe - a step that could lead to criminal charges - into the actions of Sheriff Stanley Glanz and his law enforcement agency.

The activist group said its petition stems from allegations of special treatment, questionable reserve officer training and falsified records in the sheriff's office that surfaced in the aftermath of Harris's death. The department has denied the allegations.

The Tulsa County Election Board now must verify that at least 5,000 of those signing the petition are registered voters. If that is verified, a judge would then summon prospective members of a grand jury within 30 days.

The April shooting was one of numerous incidents that have brought scrutiny to police use of force in the United States, particularly against minorities.

The Tulsa County Sheriff's Office is also under investigation by the Oklahoma State Bureau of Investigation, which is looking into possible misconduct.

(Reporting by Lenzy Krehbiel-Burton; Writing by Jon Herskovitz)