An Oklahoma judge says a civil rights group can collect signatures for a grand jury investigation of the Tulsa County Sheriff's Office following the shooting of an unarmed man by a volunteer deputy who is the sheriff's friend.

Presiding District Judge Rebecca Nightengale on Friday approved We The People Oklahoma's petition. It asks for an investigation into whether Sheriff Stanley Glanz neglected his duties and whether reservists who gave gifts to Glanz were given special treatment.

Robert Bates, a longtime friend of Glanz, is charged with second-degree manslaughter in the April 2 shooting death of Eric Harris.

The group has 45 days to collect 5,000 signatures from county voters to authorize an order impaneling the jury.

A sheriff's office spokesman didn't immediately return a call from the Associated Press Friday.