(CNN) Yes, Cleveland police Officer Michael Brelo stood on a car and shot the unarmed black occupants 15 times just after officers first riddled it with bullets. But a judge ruled Saturday that, partly because Brelo reasonably believed he was in danger, he's not guilty of a crime.

Concluding just one of several police use-of-force cases prompting outrage in Cleveland, a Cuyahoga County judge decided that Brelo was not guilty of voluntary manslaughter and felonious assault in the 2012 deaths of Timothy Russell and Malissa Williams following a 22-mile car chase.

Emotions among people upset at the verdict ran high outside the Cleveland courtroom. Some held up signs and chanted "no justice, no peace," words heard in recent months in places like Ferguson, Missouri, and New York, where massive demonstrations sprung up after African-Americans died at the hands of white police officers.

"All I know is that I don't trust police no more. No police. None," said Malissa Williams' brother Alfredo Williams. "I can't recover from this. ...This verdict isn't real. This verdict is fake."

What led to the deaths of Russell and Williams, prosecutors said, was a chase that began when a car driven by Russell backfired -- a noise that officers mistakenly thought was caused by gunshots -- in Cleveland on November 29, 2012.

It turned out that neither Russell, 43, nor Williams, 30, were armed, but Russell led numerous police officers on a 22-mile chase -- sometimes at speeds above 100 mph -- before ramming a police car in a middle school parking lot in East Cleveland, police said.

Brelo and 12 other officers fired more than 100 times in eight seconds at the car, after which, according to prosecutors, the pair could no longer be a threat.

But Brelo exited his car, got on top of Williams' car's hood and "fired at least 15 shots ... downward through the windshield into the victims at close range as he stood on the hood of Mr. Russell's car," Cuyahoga County Prosecutor Timothy McGlinty said.

Judge John P. O'Donnell, who rendered Saturday's verdict himself after a multiweek, nonjury trial, spelled out the reasons for his decision:

• The officers' first round of gunfire was permissible because they had reason to believe they and the public were at risk, in part because other officers told them the pair had weapons, that one of them had fired, because Russell led them on a chase for so long, and because of the ramming.

• Brelo's second round was permissible because a reasonable police officer could decide that, even after the 100 shots, the threat might not have been over in part because the pair might still have been moving.

• Evidence shows Brelo's gunfire caused at least one wound each to Russell and Williams that would have killed either of them. But they suffered other lethal wounds, probably from other officers' guns.

• Since evidence doesn't prove Brelo's shots were the ones that killed the pair, he can't be found guilty of voluntary manslaughter.

• Brelo also is not guilty of a lesser possible charge, felonious assault, because it wasn't necessarily clear the threat was over.

Brelo's lawyer celebrated O'Donnell's decision and the efforts that led up to it. He portrayed the case as a "David vs. Goliath" fight, with his client being the underdog.

"The prosecution in this case spared no expense and was, in fact, ruthless," attorney Patrick D'Angelo told reporters. "But notwithstanding that, we fought tooth and nail, as you saw in this courtroom."

Mayor calls for calm

The police department fired one supervisor, demoted two and suspended 72 officers in 2013 after a review panel determined they violated policies in connection with the 2012 chase and shooting. The suspensions ranged from one day to 30 days.

The department still has yet to finalize punishments for the 13 officers involved in the shooting, including Brelo, because it was waiting for the court case to end, Police Chief Calvin Williams said.

Brelo will remain on unpaid suspension until a review committee completes its investigation of him and the other 12.

"(The public) can be assured that we ... will make sure that any and all violations of our policies and procedures will be dealt with," Williams said.

Cleveland Mayor Frank Jackson told reporters Saturday that the public's reaction to the verdict would "define us as a city and define us as a people."

Jackson said he will support peaceful protests, but said anyone who takes actions "that cross the line cannot and will not be tolerated."

Brelo had told investigators he thought he and his partner were in danger, believing the couple in the car were shooting while they were in the parking lot, CNN's Martin Savidge reported

Brelo told investigators, "I've never been so afraid in my life. I thought my partner and I would be shot and that we were going to be killed."

Brelo's defense argued that not only did he and other officers believe the suspects were armed and that the officers' lives were in danger, but also that prosecutors couldn't be certain whether Brelo's final 15 shots were the fatal ones, CNN affiliate WJW reported.

He would have faced three to 11 years in prison on each voluntary manslaughter count had he been convicted.

Brelo was indicted in May 2014. Five other officers face charges of dereliction of duty in the chase and shooting.

The verdict comes during a 12-month period in which the deaths of other African-Americans at the hands of police or while in police custody -- in Missouri, New York, Baltimore as well as Cleveland -- have caused turmoil in American cities.