(CNN) An Ohio judge declared a mistrial Friday in the case against former University of Cincinnati police Officer Ray Tensing , who fatally shot Samuel DuBose during a traffic stop in July 2015.

DuBose's killing was one in a series of high-profile, officer-involved shootings that sparked nationwide protests over the use of force by police. Tensing, who is white, was fired from his job and arrested after the shooting. He remains free on bail.

Shortly after 2 p.m. Friday, Judge Leslie Ghiz declared a second mistrial in the murder case after receiving a note from the jury.

"We are almost evenly split regarding our votes towards a final verdict," the note read.

"We have given this extensive deliberation with opportunity for both sides to express their positions. We cannot proceed coming to a unanimous decision."

Tensing stared straight ahead with no expression before putting his head down in his hand. DuBose's family left the courtroom moments after the judge declared a mistrial following about 30 hours of deliberations over five days.

Under a light rain, both families walked out of the courthouse without comment.

The Rev. Peterson Mingo, an activist and friend of the DuBose family, escorted the victim's mother, Audrey, and his brother, Aubrey, to a waiting car.

"Right now, the family wants peace," he told reporters. "The family wants reconciliation. They don't want any violence. That's not the way they want Sam remembered. They want him to be remembered as the generous, caring young man that he was -- as a father and a credit to the community."

DuBose's mother expresses solidarity

In a statement, Audrey DuBose thanked the community for its support, commended the prosecution's "strong presentation" and invoked the names of other men around the nation killed by police officers who were not convicted.

"We stand with the families of (Terence) Crutcher of Oklahoma, Philando Castile of Minnesota, Freddie Gray of Maryland, and Sylville Smith of Wisconsin and demand justice for all these men who have been murdered by police officers who have escaped guilty verdicts."

She demanded a retrial and called for peaceful protests. The judge gave the prosecution until July 24 to decide whether to try Tensing a third time.

Mayor John Cranley, at a news conference, expressed his condolences to the DuBose family and the right of residents to protest peacefully. "As I have said many times before, I do not believe that Sam DuBose should have been killed in that situation," he said.

Cranley debunked claims that some downtown businesses were closing amid concerns over demonstrations.

"Just because we may not like the way things happened in the case today doesn't mean that Cincinnati is not going to move forward," the mayor said.

Convictions are rare in police shootings

Tensing was the third US law enforcement officer to be tried for shooting a black man in the last week. None was convicted.

"Across the nation, we've seen a lot of things," Mingo said.

"Some things we'll never be able to understand or explain. As I tell people all the time, there's always a final court. It won't be here on Earth... There will only be one judge, and his decision will be final."

The former cop was tried at a time of increasingly strained relations between law enforcement officers and the communities they serve.

On Wednesday, Dominique Heaggan-Brown, the former Milwaukee police officer who fatally shot Sylville Smith during an August 2016 foot chase, was found not guilty of first-degree reckless homicide.

"It's a sad day," City Council member and mayoral candidate Yvette Simpson said near a gaggle of protesters outside the Cincinnati courthouse. "Justice should apply to everybody. This isn't just a city issue. This is happening around the nation. We have a problem when the justice system doesn't apply equally to everybody."

Protesters, including some wearing Black Lives Matter shirts, gather outside the Hamilton County Courthouse during a demonstration.

Another deadlocked jury

Earlier Friday, Ghiz ordered the deadlocked jury to resume deliberations after more than 27 hours in the jury room.

In a note, jurors wrote, "We are unable to come to a unanimous decision on either count after thorough deliberation. How should we proceed?"

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Ghiz told the jurors, "Ladies and gentlemen, I'm going to send you back for a little while longer," before then reading a charge encouraging them to reconsider their positions and listen to one another as they deliberated.

In November, Tensing's first trial also ended in a mistrial after more than 25 hours of deliberations.

Tensing was charged with murder and voluntary manslaughter. He testified he shot DuBose because he feared for his life after his left arm became trapped inside DuBose's moving car on July 19, 2015.

'Threat to his life and well-being'

In closing arguments, Tensing's attorney, Stew Mathews, told the jury that DuBose "elected to start that car, put it into gear and take off with Ray Tensing's arm trapped inside it. I submit to you that is a threat to his life and to his well-being."

Prosecutors broke down body camera video frame-by-frame to rebut Tensing's assertion that he was being dragged down the street.

Hamilton County Assistant Prosecutor Seth Tieger told the jury that Tensing made a tactical error when he reached his left arm inside DuBose's car and then escalated the problem by firing his weapon.

'Ray Tensing had a choice'

"Ray Tensing had a choice to make that evening," Tieger said. "Do I disengage and let Sam DuBose drive away or do I kill him?"

Asserting the video did not definitively prove the prosecution's arguments about whether Tensing was dragged, Mathews reminded the jury of "Sully," the 2009 movie about airline pilot Chesley Sullenberger who became a hero by making an emergency landing on the Hudson River with no loss of life.

Using computer simulations, federal investigators argued that Sullenberger made a bad decision and could have reached nearby airports to land.

"They were about to hang him out to dry," Mathews said, but authorities eventually came down on the pilot's side because "human factors" were considered.

Tensing pulled DuBose over because his car didn't have a front tag and because his back tag was registered to a driver with a suspended license, DuBose's girlfriend, Mathews said.

Mathews said DuBose had motive to drive away from the traffic stop because he lacked a license and carried a felony amount of marijuana in the vehicle.

Tieger agreed with defense attorneys that DuBose did not comply with Tensing's commands but said that wasn't justification to shoot.

"Noncompliance does not equal not guilty," he said.

University of Cincinnati settles with family

After his arrest, Tensing was released from custody after posting 10% of his $1 million bond.