Judge Sharon Holmes declared the mistrial in the case of former Tulsa police officer Shannon Kepler, who was charged with first-degree murder for the fatal shooting of 19-year-old Jeremey Lake in August 2014. Just weeks before the shooting, Lake started dating Kepler's then-18-year-old daughter, Lisa.

On Friday, a deadlocked jury resulted in the third mistrial in the murder case of a white former Oklahoma police officer accused of killing his daughter's Black boyfriend.

Tulsa County Dist. Atty. Steve Kunzweiler said he was shocked that a mistrial was declared after such short jury deliberations, reported Los Angeles Times.

"I've never encountered a dynamic like this in 25 years of practice," Kunzweiler told reporters after the declaration. "In my opinion, there should be some compulsion placed on jurors to reach a verdict."

Holmes had instructed jurors that they could convict Kepler of first-degree murder or the lesser charge of manslaughter. When the jury deadlocked at 6-6, Kunzweiler said it was unclear if the breakdown was six for conviction and six for acquittal or six for murder and six for the charge of manslaughter.

Kepler was a 24-year-police veteran who retired after he was charged with murder. According to Kepler, he was trying to protect his daughter, who was living in a homeless shelter.

During her testimony, Lisa Kepler told jurors her parents dropped her off at the shelter because she was sneaking out at night. While at the shelter, she said she met Lake, who would go there to help people, according to Tulsa World.

Kepler said that Lake said she could stay with him because “once you’re 18 at the homeless shelter, you’re shark bait. Everybody wants to sink their teeth into you, you know what I mean?”

Once her father saw on Facebook that she had started dating Lake, he looked up the address and drove there in his SUV.

Lisa Kepler testified she and Lake had walked to a nearby underpass to give water and food to the homeless people who slept there and saw the SUV parked in front of Lake’s house when they returned. She said her father rolled down the window and asked her what she was doing there, and she told Lake she wanted to walk back to the house. She said when she turned her back to go back to the house, she heard several gunshots and then saw Lake lying on the ground as the SUV drove off.

Kepler told investigators he was acting in self-defense because Lake was armed with a semi-automatic weapon, but police didn't find a weapon on Lake or at the scene. Lake's aunt said her nephew was reaching out to shake Kepler's hand to introduce himself when Kepler fired.

Pam Wilkins, Lake's aunt, said his extended family is deeply frustrated by the third mistrial.

"But I'm not giving up hope," she told the LA Times. "We're believing in God and justice for Jeremey."