A five-year-old slaying victim was often struck with a pellet gun and choked unconscious by one of her accused killers, the girl's stepbrother told a Manitoba court Wednesday.

The body of Phoenix Sinclair, seen here in an undated photo, was discovered in 2006 on the Fisher River reserve. (Family photo)

Karl McKay would play the macabre games with Phoenix Sinclair regularly before she died, the 18-year-old said. He told the court how his father would shoot the little girl with his younger son's pellet gun and tell her to "run."

"He would shoot her for the fun of it," he said, adding that the girl would be targeted as she took out the garbage.

"She would cry."

McKay's son also demonstrated for jurors how his father and Samantha Kematch, Phoenix's biological mother, played “chicken.”

Standing up, the boy showed how McKay would grab the girl by the throat and choke her. Phoenix would black out and McKay would throw her on the tiled floor where she would twitch, he told the court.

"She made a weird scream," he said. "Like someone cut off her arm. She was screaming to death."

Kematch and McKay, her common-law husband, are accused of leaving Phoenix to die on a cold basement floor in 2005 after months of abuse. Her body was found wrapped in plastic in a shallow grave near the Fisher River garbage dump in March 2006.

Both have pleaded not guilty to separate charges of first-degree murder.

The couple is also accused of trying to pass off another child as Phoenix to convince welfare investigators and the RCMP that their daughter was still with the family — partly in order to apply for benefits in the little girl's name.

McKay's eldest son said he visited his father and Kematch at their home in Fisher River, Man., several times before Phoenix died. The girl, who used to be "chubby all over," was "skinny" by April 2005, he said.

He told the court he noticed cuts and bruises on Phoenix’s face and head.

When he visited, McKay's son said he never saw Phoenix eat or use the bathroom. When he tried to give her food, he said he was threatened by Kematch.

"I waited until those guys left and gave her food," he said before breaking down in tears. "They didn't help her."

Kematch's attorney on Wednesday characterized McKay as the perpetrator of most of the abuse. McKay's lawyer, meanwhile, argued that Phoenix's injuries were not intentional, but the result of horseplay.

Defence lawyer Mike Cook suggested McKay was simply emulating "fun choke holds" he saw performed in televised professional wrestling matches, and was surprised when Phoenix became hurt.

"Basically dad was doing the same stuff people do on TV," Cook said in his cross-examination. He also suggested the pellet gun shots were accidental.

"No," McKay's son said shaking his head.

He also disagreed with Kematch's lawyer, Roberta Campbell, when she said the woman was angry when McKay's son tried to feed Phoenix junk food.

In a videotaped interview with the RCMP that was also played in court, Kematch said her daughter was sometimes forced to eat her own vomit with her hands.

She said she wanted to help Phoenix but McKay wouldn't allow it.

"She'd start crying and he'd get all mad," Kematch said in the interview. "Sometimes he would just beat her for nothing."

In discussing Phoenix's death, Kematch said she McKay had hit the girl, causing her head to strike the basement floor where she was left, naked, overnight. When someone went to check on her the next day, the girl wasn't breathing.

McKay then scrubbed the basement floor and painted it, she said. She threatened to go to the police months later but was scared, Kematch added. "I feel stupid," she said. "I knew it wasn't right. She didn't deserve anything like that. I think about this every day. I think about her lots … How I wish she was here and everything."

"I know I can't hide from this," she said. "I knew this day would come."

The trial is expected to last until mid-December.

With files from the Canadian Press