(CNN) A mistrial was declared Saturday in the murder trial of former University of Cincinnati police Officer Ray Tensing in connection with the fatal July 2015 shooting of motorist Sam DuBose during a traffic stop.

The jury of six men and six women deliberated for more than 25 hours before Hamilton County Common Pleas Court Judge Megan E. Shanahan declared a mistrial. The sequestered jury started deliberations Thursday morning.

Tensing testified this week that he was being dragged by the left arm when he reached up and shot DuBose.

Prosecutors told the jury that Tensing wasn't being pulled by the car and didn't need to fire the single shot at Dubose's head.

After the mistrial, Prosecuting Attorney Joe Deters said he will make a decision on whether to retry the case by November 28.

"We're going to look at what we did in this trial and make an assessment ... as to whether or not we have a probability of success at trial," he told reporters outside the courtroom.

He added, "I still think it's murder and I think that we proved it."

Much of the shooting was recorded on the body camera of the one-time officer.

"If we did not have that body cam there would not have been charges filed," Deter told reporters. "Clearly it was the heart of the case."

Dubose's family 'really upset,' attorney says

DuBose, who was black, was killed in the same time period that saw several controversial officer-involved shootings -- including those of Tamir Rice in Cleveland, Michael Brown in Ferguson, Missouri, and Walter Scott in North Charleston, South Carolina.

Tensing, who is white, was fired from his job, arrested and indicted on murder and voluntary manslaughter charges. He was released from custody after posting a tenth of his $1 million bond.

"What we do know is that (the jurors) were leaning toward acquittal on murder, and they were leaning toward conviction on the voluntary manslaughter, but they just couldn't come to an agreement," Deters said.

There was no immediate reaction from Tensing's attorney.

JUST WATCHED DuBose's sister upset by 'devastated' officer's words Replay More Videos ... MUST WATCH DuBose's sister upset by 'devastated' officer's words 02:20

Attorney Al Gerhardstein, who represents the DuBose family, told CNN affiliate WCPO-TV, "They're really upset and they certainly want another trial."

Hundreds gathered outside the courthouse later Saturday to protest the verdict before merging with others demonstrating against the election of President-elect Donald Trump.

Cincinnati Mayor John Cranley on Saturday appealed for calm and said he hoped Tensing will be retried.

"It's important for everyone to remember the judicial process is not over," he told reporters.

Additional police officers were out in case of protests, city officials said.

"I understand that people are upset," Cranley said. "We respect everyone's right to be upset. This is America. ... We have every reason to believe that the protests -- which are justified -- will continue to be as peaceful as they have been."

Cranley does not expect protests to disrupt city life.

"Cincinnati is safe and open for business," he said.

Tensing's emotional testimony

Tensing testified Tuesday he had reached into the car to try to grab the car keys from the ignition but DuBose started the car and began to drive away.

Tensing said his left arm was caught and he started to fall.

"I remember thinking, 'Oh, my God, he's going to run me over and he's going to kill me,' " an emotional Tensing said.

The officer, who then 25, said he reached up with his gun and fired at DuBose's head, which he could see above the bottom of the driver's window frame.

JUST WATCHED Campus cop indicted in killing of unarmed black man Replay More Videos ... MUST WATCH Campus cop indicted in killing of unarmed black man 02:44

Under cross-examination, Deters showed Tensing several snippets from the video. Deters contended the video proves Tensing's arm wasn't caught, that he was standing when the shot was fired, and the car didn't accelerate until after DuBose was hit.

Tensing, who is 6 feet 3 inches, disagreed and said his chest-worn body camera showed the perspective of a man who was being dragged.

The traffic stop

After making the July 19, 2015, stop, Tensing asked DuBose for his license. DuBose couldn't find it and was acting "squirrelly," Tensing testified.

Tensing tried to open the Honda Accord's door, but DuBose used his left hand to hold it shut. After that, Tensing reached into the car-- and at that moment, his body camera shook out of focus.

"Shot fired! Shot fired!" someone yelled moments later.

DuBose's car rolled for about a block before crashing. He later died.

JUST WATCHED Attorney: Ex-University of Cincinnati cop was defending himself Replay More Videos ... MUST WATCH Attorney: Ex-University of Cincinnati cop was defending himself 03:32

The video has been a vital piece of evidence for the prosecution, but it's hard to see what happens in key parts of the footage.

There is a little more than a second between the moment Tensing reached in the car and when he pulled out his gun. It's hard to hear the gunshot. There's a bang, but the camera shakes so much that viewers are unable to see the shooting clearly. In court, prosecutors showed one frame at a time while cross-examining Tensing.

Deters at the time called the shooting "the most asinine act I've ever seen a police officer make."

The University of Cincinnati later commissioned an independent review that found Tensing had led his department in the number of stops and citations, and that more than 80% of them involved minorities.

In court, Tensing said he often didn't know the race of a person until after he approached the vehicle window.