Daunte Wright's girlfriend tried to stop his bleeding with a belt as he gasped for air, she testified at ex-officer Kim Potter's manslaughter trial

(CNN)The passenger in Daunte Wright's car when he was killed was the "only one out of everybody there that was trying to help him," the young woman testified Thursday in the trial of the then-officer who fired the fatal shot during an April traffic stop in Minnesota.

Alayna Albrecht-Payton testified in court in the trial of Kimberly Potter, the former Brooklyn Center officer who has said she mistook her gun for a Taser and accidentally shot Wright, a 20-year-old Black father. Potter has pleaded not guilty to first- and second-degree manslaughter.

Albrecht-Payton, also 20, said she had just recently started a boyfriend-girlfriend relationship with Wright when he was killed April 11.

"We were never really official because we didn't get the chance to," she said.

Police pulled Wright's car over and later told him to step out but did not say why, Albrecht-Payton testified.

"He was really scared. Like, I've never seen him like that before because if you know Daunte, like, he's just really happy, he's positive, and you can't really be like sad or depressed or angry or mad around him, and, like, he was just so nervous," she said through sobs.

After that, Albrecht-Payton was the "only one out of everybody there that was trying to help him," she testified.

She described trying to help stop Wright's bleeding with a belt and a piece of clothing she found in the car. Albrecht-Payton called his name as he gasped for air, she said.

"I replay that image in my head daily," she said.

Thursday's testimony focused on more video footage, Wright's girlfriend and more officers telling jurors their accounts of April 11 with one saying he provided medical assistance to Wright.

Potter's attorneys asked for a mistrial, claiming prosecutors spent most of Thursday focusing on the events after the fatal traffic stop shooting, such as the car crash and the medical response. Defense attorneys argued it was prejudicial and had little relevance to the manslaughter allegations in the case.

"We have spent the day rather on an accident that was caused by Daunte Wright's excessive speed," defense attorney Paul Engh said. "And then we spent an unending, it seems, amount of time on that aspect of the case without any time addressed to the gravamen of why we're here. There is a body of evidence that holds that where the state spends an inordinate amount of time presenting prejudicial evidence that has little relevance."

Minnesota District Court Judge Regina Chu denied the motion for a mistrial.

Wright's death prompted several days of protests in the Minneapolis suburb and rocked a metropolitan area scarred by other police-involved deaths. It also reignited national conversations about policing and the use of force against people of color.

'No mom should have to see their son dead on the phone'

During cross-examination Thursday, defense attorney Earl Gray questioned Albrecht-Payton about marijuana. Albrecht-Payton testified she and Wright had smoked marijuana shortly after waking up that day, but it did not have an effect on them, she said.

Albrecht-Payton sobbed on the stand and apologized for showing Wright's mother her son's dead body via a FaceTime video call. The elder woman, Katie Bryant, gave emotional testimony a day earlier about the same moments.

"No mom should have to see their son dead on the phone, on a video call out of nowhere," Albrecht-Payton said Thursday.

Bryant said her son had called her to say he had been pulled over.

Bryant heard an officer tell her son to step out of the car before the call disconnected, she said. Bryant called several more times before making a FaceTime call to her son.

Bryant said a woman answered the phone screaming, saying her son had been shot.

"She faced the phone towards the driver's seat. My son was laying there, he was unresponsive, and he looked dead," Bryant testified. "And then I heard somebody say, 'Hang up the phone,' again, and it disconnected again."

Bryant said she called 911 to get the address of her son's shooting. She was so distraught that a neighbor drove her to the scene, where she stayed for hours, refusing to leave until his body was removed, she said.

Bryant told jurors her son's body was covered with a white sheet and she recognized him by his tennis shoes.

"It was the worst day of my life," she said.

Bryant still has scars on the inside of her mouth from biting the insides of her cheeks so hard, she said.

"I thought it was a dream, and if I bit the insides of my cheeks then I would wake up," she said. "But I didn't wake up."

During cross-examination, Bryant told the defense she knew her son did not have a driver's license. She said she did not know there was a warrant for Wright's arrest and that he used marijuana.

Video shows Brooklyn Center officer drawing gun on Wright's vehicle after crash

After Potter shot him, Wright put the car in drive and took off and later crashed into a fence, Officer Anthony Luckey, a trainee working with Potter at the time, testified Wednesday.

Thursday, jurors were shown video of Wright's car crashing as well as video from the aftermath of the shooting.

One video shown was home security footage belonging to Kerry Blanksi, who lives in the area where Wright's car crashed.