An East Pittsburgh police officer who fatally shot an unarmed black teenager in the back last week was charged with homicide Wednesday after giving investigators inconsistent statements about whether he saw a gun before he opened fire. The officer, Michael Rosfeld, turned himself in on Wednesday, according to court records.

District Attorney Stephen Zappala said during a press conference Wednesday that Rosfeld’s actions were intentional and were not justified as an attempt to prevent death or serious injury.

On the night of June 19, Rosfeld shot 17-year-old Antwon Rose Jr. three times in the back as he and another teenager ran away from a vehicle during a traffic stop. Rosfeld had stopped the car Rose was in because it matched the description of a vehicle involved in a drive-by shooting about 13 minutes earlier that night. Rosfeld told investigators that he had ordered the driver to get out of the car and get on the ground when Rose, who was in the front passenger seat, also got out of the car. The suspect in the drive-by shooting was sitting in the back seat; the passenger in the front passenger seat did not fire any shots, according to detectives.

Rosfeld gave inconsistent accounts of what happened after Rose stepped out of the car. Rosfeld initially told detectives that Rose “turned his hand toward” Rosfeld, and the officer claimed he “saw something dark that he perceived as a gun” in Rose’s hand. However, Rosfeld’s version of events changed the next time he spoke with detectives. In his second account, Rosfeld told detectives that he did not see a gun in Rose’s hand. When pressed on the subject, Rosfeld said he was not sure what was in Rose’s hand and wasn’t sure if Rose’s arm was pointed at him when he fired his gun. On Friday, the district attorney confirmed that Rose was unarmed when he was killed. (Rosfeld had been sworn into the East Pittsburgh Police Department only 90 minutes before the incident. He had worked as a police officer in the area since 2011, and he was reportedly dismissed from his previous position at the University of Pittsburgh Police Department with cause.)

Rose was struck from behind by three bullets—the fatal shot hit his lungs and heart. In a video by a bystander posted to Facebook (note: video contains graphic content), Rose and another passenger, 17-year-old Zaijuan Hester, can be seen exiting the car. As they run, gunshots can be heard as a witness gasps, “Why are they shooting at them?” Another witness said, “He just ran—running is not a death sentence.”

Hester was ultimately charged with attempted homicide in connection with the drive-by shooting. Zappala, the district attorney, said that Rose was not involved. “By all accounts Mr. Rose never did anything in furtherance of any crimes in North Braddock,” he said.

Rose’s death has sparked a wave of protests in Pittsburgh. On Thursday, hundreds of protesters gathered outside the Allegheny County Courthouse to demand justice for Rose. The crowd chanted, “Black lives matter” and listened to a speech by activist Leon Ford Jr., who was shot and paralyzed by a Pittsburgh police officer during a traffic stop in 2012. Ford called for Zappala to hold the officer accountable for Rose’s death.

On Tuesday, a day after Rose’s funeral, dozens of protesters shut down rush-hour traffic in Pittsburgh. The crowd of people marched with their arms locked together and chanted, “Who did this? The police did this!” and “Three shots to the back, how do you justify that?”

Rose’s death is part of a pattern of predominantly white police officers fatally shooting unarmed black people in the U.S. In recent years, there have been several high-profile cases of black men being shot in the back by police officers.

In March, Stephon Clark, a 22-year-old black man, was fatally shot eight times by Sacramento police officers while holding a cellphone in his grandparents’ backyard. Six of the shots struck Clark in the back. It is not yet clear whether the officers will face charges for Clark’s death.

In April 2015, Walter Scott, a 50-year-old black man, was shot and killed in North Charleston, South Carolina, while fleeing from police officer Michael Slager after being stopped for having a faulty brake light. Slager fired eight shots toward Scott’s back, five of which hit him. A bystander’s video of the killing showed Slager shot Scott as he was running away, handcuffed him as he lay dying, and appeared to plant evidence—a Taser—beside Scott’s body.

The existence of the video separated Slager from many other police officers who have shot unarmed civilians. In many cases, it is the officer who gets to tell the story of what happened in the victim’s final moments alive—whether the officer feared for his life, or whether there was a scuffle. Their accounts are often given significant weight in assessing whether the shootings were justified. However, the video of Scott’s death was unambiguous evidence of what transpired.

Slager was fired and charged with murder—a rare occurrence for a police officer responsible for the death of a civilian. But when the case went to trial, a jury was unable to reach a verdict, and the judge ruled a mistrial in December 2016. However, Slager pleaded guilty to separate federal charges of violating Scott’s civil rights. In December, Slager was sentenced to 20 years in prison for Scott’s death.

Few police officers who shoot civilians ever face a trial. Research estimates that there are approximately 1,000 police shootings each year in the U.S. However, between 2005 and April 2017, only 80 officers were arrested for manslaughter or murder for police shootings. Of those, only 35 percent were convicted.

Slager’s conviction broke from that pattern, but it is unclear whether Rosfeld will face similar consequences for shooting Rose. The Rose family’s attorney, Lee Merritt, said the family is “going through the highs and lows that is common to this kind of situation from disbelief to anger to determination to get justice.” A preliminary hearing is set for July 6.