Portland's police chief, Larry O'Dea, resigned Monday amid criminal and internal investigations into whether he was forthright after accidentally shooting his friend during a camping trip on the other side of the state.

Mayor Charlie Hales announced the move at a news conference that had to be shifted to his office because of hecklers.

Hales said he's been disappointed by the "trial by media" and asked everyone to await the outcome of the twin investigations before passing judgment.

"If the investigations determine that some of what has been printed about Chief O'Dea's conduct turns out to be not true, I would ask you to be as energetic in clearing his name as you have been in smearing him," Hales said.

O'Dea, 54, had been chief for little more than a year when he went on the April trip to sparsely populated Harney County in southeast Oregon. He shot his friend, Robert Dempsey, in the lower back with a .22 caliber rifle. The friend was taken to a Boise hospital, but not seriously hurt.

O'Dea didn't identify himself as Portland's police chief when deputies spoke with him, and he said it appeared Dempsey shot himself in a mishap.

A deputy who interviewed O'Dea at the scene wrote in a report that he smelled of alcohol. O'Dea denied being intoxicated, and his attorney, Derek Ashton, reiterated that contention in a statement to the media on Sunday.

"Larry O'Dea did not have alcohol on his breath nor was he impaired or intoxicated," Ashton said. "He did not purposely point his gun at any person and did not knowingly discharge a firearm in the direction of his lifelong friend."

O'Dea admitted to Hales a few days after the incident that he had fired the shot. Harney County authorities didn't learn the truth until weeks later, when the victim finally spoke with an investigator.

After Sheriff Dave Ward learned that O'Dea was a law enforcement officer, he turned the investigation over to state police.

The shooting eventually became public. O'Dea was placed on paid administrative leave, replaced on a temporary basis by an assistant chief, Donna Henderson.

But Henderson and three other assistant chiefs are now under investigation for not initiating an internal investigation into O'Dea's conduct. It's all led to what Hales calls a period of "turmoil and confusion" for the Portland Police Bureau.

Capt. Mike Marshman was promoted to chief, at least until the next mayor, Ted Wheeler, takes over in 2017.

Hales, who is not seeking a second term, has been sharply criticized for not immediately telling Portlanders the chief had been involved a shooting.

One of Monday's hecklers called him a criminal for hiding information. Another repeatedly played a recorded message into a megaphone, asking Hales when he became aware of the "lies."

Hales repeatedly defended his weekslong silence, saying he was told the investigation was supposed to be swift and confidential, "and it was neither."

O'Dea had been chief since January 2015. His downfall comes a month after Sheriff Dan Staton of Multnomah County — which includes Portland — retired amid complaints that he, among other things, made inappropriate comments and created a hostile work environment.

Ironically, the man who replaced Staton on an interim basis, Mike Reese, was the Portland police chief until he was replaced by O'Dea.

Asked to explain the merry-go-round, Hales explained that police work is difficult, "particularly when people race to judgment in all things, and we expect — in 140 characters and a few minutes — to resolve every issue."