TULSA, Okla. (AP) — A grand jury should review operations at an Oklahoma sheriff’s office that sent onto the streets a 73-year-old reserve deputy who shot and killed an unarmed and restrained suspect, a judge ruled Tuesday.

District Judge Rebecca Nightingale ordered a grand jury to convene on July 20 after denying a motion by attorneys for Tulsa County Sheriff Stanley Glanz to disqualify the petition because circulators didn’t attach a 33-page summary of specific allegations against the sheriff to the signature pages. Glanz, who was attending the National Sheriffs’ Association annual conference in Baltimore, said in a statement that he would explore his legal options when he returned to Tulsa.

The petition was signed by more than 6,600 voters who want a grand jury to investigate whether Glanz neglected his duties and whether reservists who gave gifts to the sheriff were given special treatment. Only 5,000 signatures were required.

Nightingale ruled from the bench after a daylong hearing that there was nothing in the law requiring that the court-approved grand jury petition and signature pages be attached to each other. She said that if she were to dismiss the petition filed by the civil rights group We The People Oklahoma it would be putting “form over substance.”

The petition drive began after ex-volunteer deputy Robert Bates shot and killed Eric Harris on April 2 after Harris ran from authorities during a gun-sales sting operation. Bates has said he confused his handgun and stun gun and has pleaded not guilty to second-degree manslaughter in Harris’ death.

Weeks after the shooting, a 2009 memo was leaked that raised concerns about the training for Bates, a friend of Glanz who has donated tens of thousands of dollars in equipment, vehicles and cash to the sheriff’s office.

The Oklahoma State Bureau of Investigation is looking into the shooting and a Texas-based firm has been hired by the county to audit the agency. The reserve deputy program has also been temporarily shelved while the training records of all 126 reserves are reviewed.

Marq Lewis with We The People Oklahoma called Tuesday’s win “a milestone” and a victory for residents.

“It was good to see the citizens win for a change,” a jubilant Lewis said outside the courtroom. “Right now, we’re just going to celebrate.”

Glanz said in a statement that while he’s not afraid to face a grand jury, the process used by the petitioners didn’t follow what he said were “very clear and unambiguous laws governing grand jury proceedings.”

Glanz stated he has time to consider his options, citing a state law that prohibits the convening of a grand jury either 30 days before or 10 days after any election for state or county office. There is a special election July 14 to fill a position for a vacant state representative seat.

Tulsa County District Attorney Steve Kunzweiler said he has asked the state attorney general to appoint another prosecutor to coordinate the grand jury investigation because the local prosecutor has traditionally provided legal counsel and advice to the sheriff’s office. “In keeping with my office’s duty and responsibility to protect the integrity of the investigative process, it is incumbent to avoid the appearance of any conflict,” Kunzweiler said in a statement.

Attorneys for Glanz seemed to spend much of Tuesday’s hearing arguing semantics. Attorney John Carwile said the signature pages contained only a brief summary that was misleading and too general.

But Lewis disputed that, testifying that attaching the 33-page petition to each signature sheet would be too costly for his group, which operates mainly with volunteer support. Lewis’ attorney estimated it would cost around $3,300 to generate some 16,800 copies.

“It’s almost the cost of a car,” Lewis testified.