A judge acquitted Cleveland police officer Michael Brelo of all criminal charges on Saturday, clearing the 31-year-old Iraq war veteran of wrongdoing in an incident that left two unarmed suspects dead after a 25-minute high-speed chase that ended in a hail of bullets.

Though 13 officers fired a total of 137 rounds in less than 30 seconds during the November 2012 encounter that left Timothy Russell, 43, and Malissa Williams, 30, dead in a middle school parking lot, prosecutors decided to charge Brelo because he stood on the hood of Russell's 1979 Chevy Malibu and fired 15 rounds into the windshield at least four seconds after everyone else had stopped shooting.

Cuyahoga Count Judge John P. O'Donnell, however, said he could not determine if Brelo alone was responsible for firing the fatal shots. The officer could have faced up to 22 years in prison if convicted. O'Donnell spent nearly an hour summing up his conclusion in the bench trial, which does not involve a jury.

Brelo was also acquitted of lesser charges of felonious assault because the judge said his actions were justified by the circumstances of the chase, which began when Russell's vehicle backfired as he drove past Cleveland police headquarters, leading to reports that someone inside the car had fired a gun.

News of Brelo's acquittal prompted an angry protest outside the courthouse, including chants of "Hands up! Don't shoot!" The verdict comes during a period of heightened tension over the use of deadly force by police nationwide, particularly in cases that involve unarmed black suspects.

Malaya Davis, an organizer with the Ohio Student Association, said in a statement that Brelo's acquittal "is another reminder that the safety of people of color, and the notion of true and equal justice in this country, depends on concerted reforms in our systems of policing and fundamental shifts in our society to embrace greater racial justice."

"The police put on a badge that should carry a responsibility to serve us all, but instead they are using it as a shield to hide behind as they profile, harass and kill people of color," Davis said.

The Department of Justice and the FBI said they would collaboratively review testimony and evidence in the case and continue with their own assessment.

Brelo's lead attorney, Patrick D'Angelo, said that the officer's legal team was "humbled by the verdict but not emboldened by it," adding that he had never "witnessed such a vicious and unprofessional prosecution of a police officer," according to the Associated Press.

Altogether, 13 officers fired shots as they pursued Williams and Russell in a 22-mile chase that that involved 62 marked and unmarked cars.

While Russell and Williams were each hit more than 20 times, prosecutors argued that both were alive until Brelo unloaded with the final barrage of gunfire. Brelo fired a total of 49 rounds during the incident. Medical examiners testified that they could not determine who fired the fatal shots.

In addition to Brelo's case, a grand jury also charged five Cleveland police supervisors with misdemeanor dereliction of duty for failing to control the chase. All of the five have pleaded not guilty. Their trial dates have not been set.