A slowly growing, peaceful crowd of about 60 gathered outside a Cincinnati courthouse Wednesday after a judge found a white police officer not guilty in the shooting death of an unarmed black man.

Officer Stephen Roach, 27, had been charged with negligent homicide and obstructing official business, both misdemeanors, after he shot Timothy Thomas, 19, in a dark alley early on April 7. He had faced up to nine months in jail if convicted of both charges and still faces possible police department discipline.

Hamilton County Municipal Court Judge Ralph E. Winkler said Roach had been put into a do or die situation. The judge, who heard the case without a jury at the officer's request, concluded that the shooting was "not a culpable criminal act."

"Thomas' actions in running from numerous police and not following police orders ... was unfortunate," the judge said. He added that Roach's record was unblemished, while Thomas' was not, and noted that Thomas failed to respond to an order to show his hands.

The three nights of rioting following the shooting was the worst racial unrest since the Rev. Martin Luther King Jr.'s assassination in 1968. Dozens of people were injured and more than 800 were arrested in the April riots.

Additional police were on duty as a precaution when the verdict was announced but there were no disturbances.

The Rev. Damon Lynch, a black leader and minister in the Over-the-Rhine neighborhood where Thomas was shot, said he will be telling people today "to keep fighting for justice." He called the verdict "an atrocity" but said "We'll urge people to be peaceful as we have been doing for 10 weeks."

One person in the crowd outside the courthouse yelled "How is that justified."

The verdicts show "that the city is not willing to put a police officer in jail for killing a man unjustifiably," said Kabaka Oba, a Cincinnati Metro bus driver and black activists. "We believe Timothy Thomas was killed unjustifiably."

Angela Leisure, Thomas' mother, said the verdict was unfair.

"Why is it that officers are not responsible for their acts when other citizens are?" she said.

She said she was afraid a similar shooting will happen again.

"My son, I wanted him to be the last — but he won't be the last ... until serious changes are made in our police department this will happen again," Leisure said.

Roach glanced down as the verdicts were read and sighed as Winkler dismissed the court.

Roach's wife, Erin, sobbed into her hands when she heard the verdict.

Outside the courtroom, Roach said he was sorry about what happened to Thomas and that he understood Leisure's pain.

"Unfortunately, this is a tragedy for everybody involved," Roach said, holding hands with his wife. "I would give anything to change the outcome of what happened that night, but unfortunately I can't."

Roach, a city officer since 1997, was believed to be the first Cincinnati police officer to go to trial on charges of shooting a suspect to death, police officials said.

Thomas was shot in the chest. He had been wanted on 14 warrants, including traffic charges and previously fleeing police.

Winkler said Roach showed "no lapse in due care" by firing his weapon in a dangerous situation.

"This shooting was a split-second reaction to a very dangerous situation created by Timothy Thomas," Winkler said. "Police Officer Roach's action was reasonable on his part ... based on information he had at the time in that dark Cincinnati alley."

Prosecutor Stephen McIntosh said Roach ran down the alley with his finger on the trigger of his 9mm revolver when he shot Thomas, rather than keeping the finger off the trigger until a threat had been perceived, as Cincinnati officers are trained to do.

Other officers who had been chasing Thomas testified they had not drawn their weapons or perceived a need to do so, McIntosh said.

Prosecutors also said Roach hindered the police investigation, by telling homicide investigators differing versions of what had occurred.

However, Winkler said the officer cooperated with investigators.

"Many differing statements attributed to Officer Roach were not substantial, and the statements did not hamper or impede the police investigation of the incident," the judge said.

The officer initially told investigators that Thomas made a threatening move toward him, and he thought Thomas had a gun. Roach later told investigators that Thomas stepped around a corner in the alley and startled him, and that the officer accidentally shot him. Investigators found no weapon on the victim.

Thomas had run from three other police officers, scaled fences and was in a neighborhood plagued by guns, drug deals and violence, Roach's defense lawyer said. Roach was doing his job by trying to catch a man named in arrest warrants, defense lawyer Merlyn Shiverdecker said.

Shiverdecker said police homicide investigators failed to take into account how the darkness would have affected Roach's perception, or how the instinctive fear he experienced when he felt threatened could have affected what he recalled when he spoke to police about the shooting.

Shiverdecker said the officer's fear caused him to involuntarily fire his weapon.

The Associated Press contributed to this report.