The verdict came in the second day of deliberations Tuesday. The trial began more than a week ago.
While De'Maree's family can't get her back, they can get justice.
"No doing her hair. No waking her up for school. No college graduation. No marriage. No kids. I don't get any of that," said De'Maree's mom, LaToyia Jarmon-Thomas.
It's been a tough three years for Jarmon-Thomas as she lives without her daughter.
"He took my baby away from me," she told ABC13.
On the morning of Feb. 25, 2017, LaToyia Jarmon-Thomas was heading home in her vehicle, with De'Maree in the backseat asleep.
READ MORE: Gunman opens fire on car after crash, kills 8-year-old
Jarmon-Thomas had a green light and was headed through an intersection. That was when, police said, a white Pontiac Grand Prix ran a red light near Fuqua and the Beltway. Jarmon-Thomas then hit the car.
De'Maree's mom was immediately worried about her daughter.
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"I turned to her and I said, 'De'Maree.' She said, 'Yes, Mommy. What happened?' I said, 'We had a car accident. Are you okay?' She said, 'Yes, Mommy,' and went right back to sleep," Jarmon-Thomas recalled.
Minutes later, another Pontiac Grand Prix pulled up. Police said this one was driven by Payton. Officers said he started shooting at Jarmon-Thomas' car, hitting it at least four times. Two bullets went through the back passenger side of the car, killing De'Maree.
Since then, Jarmon-Thomas has been praying for justice.
"I was nervous," she said as the trial began. "Beyond nervous. My stomach was doing flips."
After eight hours, the jury reached a verdict: guilty.
Jarmon-Thomas was visibly relieved as the verdict was read, three years after losing her daughter.
"I'm elated," she said. "I've been waiting for this for three years. Three whole years."
Now, in the next phase, the jury will determine Payton's sentence, which could be anywhere between five years to life in prison.
As for the guilty verdict, Jarmon-Thomas knows her sweet daughter is smiling from above.
"She's probably like yes, my mommy finally got justice for me," said Jarmon-Thomas.
READ MORE: Man accused in murder of 8-year-old girl claims he is being held illegally
The video above is from a previous edition.
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