Trevor Dimen, who is still in custody, is seen arriving at court Monday for the start of his manslaughter trial. Dimen, 40, is accused of causing the death of his father, William. (CBC)

A Regina courtroom was the scene of an unusual spectacle Thursday as a son, accused of killing his father, cross-examined his mother.

Trevor Dimen, 40, is acting as his own lawyer at his trial on a charge of manslaughter in the April 2008 death of his father, William Dimen, 69.

Prosecutor Chris White laid out the Crown's case earlier in the week.

According to the Crown, William Dimen was critically injured falling down stairs leading to the basement of his home. The Crown believes Dimen caused the fall, following a heated argument with his mother and father.

Trevor Dimen has characterized the fall as an accident.

As the case proceeded, Dimen has been actively engaged in questioning Crown witnesses, including Elaine Dimen, his mother, who has been testifying for two days.

Dimen asked his mother if she called for help when it seemed that a confrontation was developing on the night his father died.

William Dimen, 69, died Apr. 11, 2008. (Submitted by Sherri Dimen)

"I did that once before and you were watching me," Elaine Dimen responded. "So I didn't think I would get very far."

He also asked his mother if there had been a physical fight.

"I was very scared," she answered. "Your voice was raised."

Dimen's questions often strayed into areas not directly related to the death. At one point he quizzed his mother about whether or not dancing was part of his childhood.

"Did I enjoy dancing as a child?" Dimen asked his mother. "Did I dance with my cousins?"

"I recall you played with your cousins," she replied. "I can't say if you danced with them."

The Crown was expected to wrap up his case on Friday.