A white former Oklahoma police officer Shannon Kepler has been convicted of first-degree manslaughter by a jury late Wednesday in the shooting death of his daughter's black boyfriend in 2014 after jurors in the three past trials couldn't decide whether the police officer was guilty of murder or not.

On Wednesday night, the jurors reached a verdict after around six hours of deliberation before finding Kepler, 57, guilty of the first-degree murder charge that was placed on him in August 2014 after he shot dead 19-year-old Jeremey Lake who had been in a relationship with his then-18-year-old daughter, Lisa Kepler.

The jury recommended Kepler to serve 15 years in prison and pay a $10,000 fine.

Kepler was off-duty when he shot Lake. During his previous trials, he told the investigators he had fired because he thought Lake had a firearm, however; police at the scene did not find a weapon there or on Lake.

Kepler told that Lake had been acting in self-defense when he had shot him.

"He's bringing it, I'm bringing it," Kepler said during his trial from the witness stand. "It was either him or me. I'm not going to stand there and get shot," according to Tulsa World.

Kepler claimed he tried to protect his daughter because she had been living in a crime-ridden neighborhood then. Lisa said in 2014 that she had been kicked out of her house a week earlier to the shooting. She said her parents left her at the Tulsa Day Center for the Homeless, where she met Lake and they began a relationship.

Lisa had also said that she attempted to stop her father too from firing the gun at Lake, but she was forced to run behind a bush in their home's front yard when the officer also tried to shoot her. In an email to KWTV, police confirmed that “the suspect shot at the female but missed."

Kepler had allegedly shot Lake as the teen walked up to his vehicle in order to introduce himself as his daughter's boyfriend. Kepler and his wife initially fled after the shooting but turned themselves to the authorities later that day. His wife had been booked on a complaint about the accessory to murder.

Kepler retired from the department after he had been charged. Jurors in Kepler's earlier three trials had deadlocked 11-1, 10-2 and 6-6, which had forced the judge to declare mistrials. The jurors had convicted Kepler of recklessly using his firearm in the first trial, even though they could not decide on his murder charge, the Washington Post reported.

Lead defense attorney Richard O’Carroll told the jury in his closing argument not to let “political pressure” influence them into making the judgment about his client, who had been a longtime Tulsa police officer with a clean record.

"It’s a tragic situation, but don’t make it a political prize," O’Carroll said.

District Attorney Steve Kunzweiler and Assistant District Attorney Kevin Gray said in their respective arguments that people with otherwise clean pasts might not always make the right choices. They also accused Kepler of lying in his testimony about how he had shot Lake and why Kepler once drove to Lake’s home while off-duty. They alleged that the former officer “hunted” the teen down and allegedly initiated an altercation with him because he was “the boy” Lisa was in a relationship with after they had kicked her out of their house.

"He got himself caught up," Kunzweiler said of Kepler. "It just doesn’t play out the way he wanted it," according to Tulsa World.