Police officers are rarely convicted of murder in connection with on-the-job fatal shootings.

That's why it was a historic moment on Aug. 28 when Mike Snipes, Dallas County's first assistant district attorney, convinced a jury to convict former Balch Springs police officer Roy Oliver of murder and sentence him to 15 years in prison.

Oliver, who is white, fatally shot 15-year-old Jordan Edwards, who was black, as Edwards was leaving a house party with his friends last year. Edwards was unarmed. Oliver has claimed he was acting in defense of his partner when he fired his weapon.

Regardless of the circumstances, juries often sympathize with police officers charged with crimes, given the dangerous nature of their jobs, which sometimes involve split-second decisions on whether to end a person's life with a gun.

Snipes believes he won a conviction because, in addition to having police body camera video evidence showing that it was unnecessary for Oliver to shoot the boy who was fleeing the party because of the sound of nearby gunshots, he had several eyewitnesses to Edwards' slaying.

But, Snipes said, the conviction is owing just as much to the victim—a young, smart, athletically talented African-American teen who stayed out of trouble, got good grades, and planned on going to college.

“It was pure luck. I can say now it's nearly impossible to get a convictions in these cases,” Snipes said of the victory. “If you take away any one of those, we lose.”

“And I'll tell you this. I'm by no means the best trial lawyer in that office,” said Snipes, whose primary job as first assistant DA is managing hundreds of young Dallas prosecutors. “But I knew early on it was going to be a gut wrenching. And I didn't want any of my kids taking that case, losing it, and having to live with it for the rest of their lives.”

Dallas County District Attorney Faith Johnson decided to charge Oliver with murder just days after Edwards was killed. It was a highly unusual move as it usually takes months before prosecutors charge police officers with crimes—if at all, given their close relationship with law enforcement. Snipes told Johnson that he wanted to be the office's lead lawyer on the case, along with prosecutors George Lewis and Shawnkeedra Martin.

“He asked me immediately,” said Johnson, who agreed to Snipes' request and participated in the case herself by cross-examining a witness and helping give the closing argument. “I knew that Mike is a hard worker, he is intense, and he would do everything he could to represent this office and this family in a great way.”

Snipes' primary job at the office after Edward's slaying was Oliver's prosecution, Johnson said.

“He just worked this case day and night. He would be here on Saturday and Sunday,” Johnson said. “And there wasn't a witness in the case that he didn't talk to at least four times—sometimes seven. He knew every second of everything that happened in the case. I don't think I could have found another prosecutor who was as committed as he was.”

Daryl Washington, a Dallas attorney who represents the Edwards family, attended every day of Oliver's murder trial and rated Snipes' trial performance as “stellar.”

“Mike was prepared, believed in the case, and it showed when he presented the case to the jury,” Washington said. “One of the things Mike and his team were really able to do was get the jury to take the police uniform off and look at this person as an individual.

“Police officers have a tough job, and bad police officers get lumped in with good police officers,” he continued. “And Mike was able to convince the jury not to give this officer the benefit of the doubt.”

The jury's decision to give Oliver a fraction of the 60 years in prison that Snipes had requested was a disappointment to the Edwards family, Washington said.

“Obviously, the family wanted this officer to serve more time in prison for taking the life of Jordan Edwards and risking the lives of other teenage boys,” Washington said. “But when we were able to sit back and think about this and realize that this police officer was found guilty of murder and will spend 15 years in prison, it's a start.''

Bob Gill, a Fort Worth attorney who represented Oliver in the trial, said his client will appeal his conviction and sentence.

“Our defense was that he was defending his partner,'' Gill said of Oliver. “Our client testified that he feared for the life of his partner and that caused him to do what he did.”

Snipes said a big part of his motivation in the case was that he came to adore Jordan Edwards—a teen he'd never met.

“I can't overemphasize this,” Snipes said. “To me, Mike Snipes, the case was never a political case. It wasn't about white vs. black or Democrat vs. Republican. I didn't do it because of that. I did it for the kid. If you knew the kid like I did, you would love him.”