A retired judge charged with murder was apparently angry when he found out detectives would search his apartment for clues following the death of his wife.

That's what Sgt.-Det. Josée Lajeunesse of the Quebec City police testified Thursday at the murder trial of retired judge Jacques Delisle.

Delisle, now 77, is charged with the first-degree slaying of his wife, Marie-Nicole Rainville, 71, in what is believed to be the first time a Canadian magistrate faces such a serious charge.

The Crown alleges that Delisle shot his wife in the head. The 71-year-old woman was found in the couple's condo in Quebec City's Sillery district in November 2009.

Delisle insists that his wife, who was paralyzed on half her body following a stroke, committed suicide.

Authorities had originally agreed that Rainville's death was a suicide, but a police investigation eventually led detectives to a different conclusion. Delisle was arrested and charged in June 2010.

Lajeunesse, a Quebec City police officer, told the court Thursday that Delisle protested upon hearing about plans to search the house that he didn't kill his wife.

Lajeunesse says she found the comment – that he hadn't killed her – shocking. She says that, initially, the thought had never even crossed her mind.

She says Delisle didn't want to allow access to the apartment.

Later, he sought to be present and tried to take control of the investigation, she says.

During cross-examination, Delisle's lawyer, Jacques Larochelle, said it wasn't surprising that Delisle wouldn't want police to search the home without his presence.

Larochelle noted that after that argument, Delisle allowed police to enter the apartment but claimed the right to be present.

Delisle's trial is expected to last up to four weeks.

The trial of the retired Quebec Court of Appeal justice began this week, with the Crown's assertion that Delisle had a mistress.

The trial heard that he had expressed some desire to start a life with his former secretary.

She is expected to testify later in the trial.

Delisle had retired from the Quebec Court of Appeal just months before his ailing wife was found dead. He had retired to take care of her.

The jury trial has been hearing from police witnesses since Tuesday.

Police have already testified that gun-powder residue found in Rainville's hand was located deep in the palm, a strange location for someone who would have used the gun on herself.

On Wednesday, ambulance technicians and a nurse from the hospital testified that Delisle told them separately not to attempt to resuscitate Rainville and to respect her wish to die.

Rainville was declared dead in hospital.