Deters said Dubose "was subdued," adding that Tensing had his licence plate number.
"This office has probably reviewed upwards of hundreds of police shootings, and this is the first time that we've thought this is without question a murder," he said.
Deters said Tensing fell backwards after shooting Dubose in the head.
Deters said that if Dubose began to leave, the officer should have just let him go rather than shoot him in the head.
"Could you imagine the outrage you would have if this was your kid, if this was your brother, over a stop like this?" Deters said.
"And he didn't do anything violent towards the officer. He wasn't dragging him. And he pulled out his gun and intentionally shot him in the head."
The University of Cincinnati said it had fired Tensing after his indictment. Tensing, who was on administrative paid leave, turned himself in yesterday.
Audrey Dubose, mother of the slain driver, said she knew and prayed that the truth about her son's death would be revealed.
"I'm so thankful that everything was uncovered."
She said she could forgive Tensing if he asked for forgiveness. Calling her son a righteous, joyful man, Dubose said she thought the officer should have been "locked up on day one". Mark O'Mara, a lawyer for Dubose's family, said that his relatives did not want a violent or aggressive response to the news of the indictment.
Tensing's lawyer said he was shocked that his client was indicted on a murder charge. "I kind of expected he would get indicted for something, but I certainly didn't think it would be murder," Stewart Mathews said. He said murder means purposeful killing and his client did not intend to kill DuBose.
Over the last year, a series of fatal incidents involving US police officers have sparked a national debate about how law enforcement uses force, particularly toward minorities. The deaths of unarmed black men like Eric Garner in New York and Michael Brown in Ferguson were followed by sustained protests that erupted again after the officers involved in both situations were not charged.
Police officers are rarely charged after fatally shooting people. A Washington Post investigation found that thousands of police shootings over the last decade have resulted in a few dozen officers being charged.
So far this year, more than 550 people have been shot and killed by police, according to a Washington Post database tracking such shootings this year.
- Washington Post-Bloomberg, AP