The former mistress of a retired Quebec Superior Court judge has testified at his first-degree murder trial.

On Wednesday, Johanne Plamondon was the last Crown witness to be called as Jacques Delisle, 77, is tried for the death of his disabled wife. He was charged with first-degree murder in 2010 — seven months after telling a 911 operator his wife, Nicole Rainville, committed suicide in their apartment.

The Crown alleges Delisle had grown tired of caring for his ill wife, who suffered a stroke in 2007 and was confined to a wheelchair after breaking her hip in the summer before her death.

The court had heard previously that Delisle had a "parallel" life with a mistress spanning more than two decades.

Plamondon, 57, was the judge's secretary for 26 years — the entire time he was on the bench.

She started working for Delisle the year he was appointed to the Quebec Superior Court. When he was promoted to the court of appeal, she was also promoted.

mi-nicolerainville-220

Nicole Rainville's death was initially deemed a suicide. (Radio-Canada)

Plamondon told the jury that she and Delisle were only friends and co-workers, both married, for years. It was only a few months before Rainville's stroke that their affair began, she said.

Plamondon testified that Delisle would pick her up, they'd meet for lunch, and she'd take afternoons off to be with him. She told the jury Delisle said they'd be together one day.

They discussed living together a few days before Rainville was found shot in the temple in an apparent suicide.

Plamondon said Delisle came to see her the day after his wife died. The court heard that he told her Rainville had committed suicide and that he wouldn't be in touch for a while, because there would be an investigation, and he would be busy.

Plamondon and Delisle eventually moved in together, but the relationship ended two days later when he was arrested, she said.

Earlier testimony at the trial included police officers who responded to the 911 call on the day of Rainville's death. Police reported Delisle told emergency workers not to resuscitate his wife, as that was what she wished.

Rainville's death was initially deemed a suicide — but seven months later police arrested the former judge and charged him with first-degree murder.

Delisle was appointed to the Quebec Superior Court in 1983 and sat on the Court of Appeal for 15 years. He left the bench six months before Rainville's death.

The defence will begin presenting its case on Thursday.