A preliminary hearing to present evidence against former Philadelphia Police Officer Ryan Pownall, charged last month with killing a suspect after a traffic stop in 2017, was postponed Wednesday as prosecutors and defense lawyers clashed over whether they needed the proceeding or could move straight to a trial.

Pownall, 36, was not in the Criminal Justice Center courtroom –packed with officers and supporters — and remains jailed without bail on criminal homicide and related charges. He is the first Philadelphia officer in nearly two decades to face charges over an on-duty shooting.

After a grand jury investigation, Pownall was charged Sept. 4 with fatally shooting 30-year-old David Jones in the back as Jones fled from a traffic stop in North Philadelphia in June 2017. Jones had a gun when Pownall pulled him over for riding an illegal dirt bike on the street, authorities have said, but the weapon fell to the ground before Jones started running away.

At the hearing scheduled before Municipal Court Judge Patrick Dugan, prosecutors were expected to begin disclosing the evidence that led to the charges and seek the judge's approval to move it forward to a trial. But before the hearing, the District Attorney's Office filed a motion seeking to skip the hearing and head straight to trial, arguing that the grand jury's decision to charge was sufficient to move forward.

"Simply put, to require lengthy, complex testimony from an investigative grand jury to be repeated, for the sole purpose of establishing probable cause a second time, is not only a waste of scarce judicial resources, but also a repetitious, costly, and superfluous layer of delay before trial," said the motion, signed by Assistant District Attorney Tracy Tripp.

Pownall's attorney, Fortunato Perri Jr., said a preliminary hearing should be held because the evidence does not support the charges.

"We're confident that at the end of this process, when a fair-minded court has an opportunity to review the evidence not steered in one way or the other, that Ryan Pownall will be exonerated," Perri said after Wednesday's court appearance.

That issue is being argued before a separate judge in the courthouse, and Dugan said it first needs to be resolved before he can move ahead with a preliminary hearing. He tentatively rescheduled the proceeding for Oct. 2.

The police union this month expressed outrage that District Attorney Larry Krasner had charged Pownall with the general count of criminal homicide. The charge prevents Pownall from being released on bail and opens the door to prosecutors' ultimately trying Pownall for first-degree murder, which carries a mandatory life sentence upon conviction.

In at least one other case this year — a fatal stabbing in Rittenhouse Square — Krasner's office told a judge before a preliminary hearing that it did not believe the evidence supported first-degree murder and that prosecutors instead intended to proceed on third-degree murder and related charges.

A third-degree murder charge enables defendants to apply for bail while awaiting trial and can ultimately mean a shorter prison sentence if they are convicted.

John McNesby, president of Fraternal Order of Police Lodge 5, the officers' union, said at a news conference after Pownall was charged that it was an "absurd disgrace" that Pownall had been booked on the state's most serious murder count.

"We will have a vigorous defense and expect him to be cleared, no doubt about it, to be cleared of all charges and get his job back protecting his community," McNesby said at the time.

Pownall was fired from the police force a year ago over the shooting. His family attended Wednesday's court appearance — as did Jones' — but left without commenting.

Jones' godmother, Donna Clement-Jackson, 49, said outside the courthouse: "We pray that justice will be served."