Two witnesses at the trial of a Montreal man accused of killing his ailing wife told a jury Friday the accused admitted to taking the woman's life.

Linda Desgagne, a senior nurse at the Montreal long-term care facility where Jocelyne Lizotte lived, said Michel Cadotte asked to speak to her alone after he had alerted other staff to his wife's death on Feb. 20, 2017.

Desgagne testified Cadotte told her: "I did it. I took a pillow and I suffocated her."

She described Cadotte, 57, as tearful but calm as he explained he was at his wits' end. "I just couldn't take it anymore," Desgagne testified Cadotte told her. "Call 911, I'll wait here."

Desgagne said she told Cadotte he could have sought more support from staff, before leaving him alone with Lizotte's body. She alerted her superiors, one of whom called police. She returned to tell Cadotte police were on their way and last saw him being led away in handcuffs.

Lizotte, 60, was in the late stages of Alzheimer's disease and was entirely unable to care for herself. The couple had been married for 19 years.

"I had sympathy for Mr. Cadotte," Desgagne said, explaining that they had spent time in close contact over the care of Lizotte.

The nurse, who has more than 30 years experience, said Cadotte was closely involved in Lizotte's care at the centre where she'd lived since January 2014, describing his interventions with staff as polite but firm.

Shortly after the law allowing medically assisted death came into effect in Quebec, he inquired in February 2016 whether Lizotte would be eligible.

Desgagne said she was one of three staff at the Emelie-Gamelin centre who met with Cadotte and explained Lizotte did not meet the criteria for the life-ending procedure because she was not capable of making the request herself and she was not considered to be at the end of her life.

She said Cadotte did not react strongly but said he would seek a legal opinion. "He seemed to understand what we were saying. He didn't bring it up again," Desgagne testified.

Later Friday, the brother of Lizotte's first husband took the stand. Michel Desautels is married to Lizotte's childhood friend, and the couple remained friends with Lizotte after she married Cadotte following the death of Desautels' brother.

Desautels said he and Cadotte communicated frequently. He testified Cadotte called him to tell him Lizotte was dead. "It was me," Cadotte told him, which he understood to mean he had killed her.

The retired Montreal man said the couples saw each other frequently, but as Lizotte's health deteriorated following her diagnosis at age 49, those visits became rarer. He testified the last time the couple saw Lizotte in 2016, she was no longer able to communicate or acknowledge their presence, rocking back and forth while strapped to her chair.

Desautels said it simply became too difficult for his wife to see her longtime friend in that condition.

The trial resumes Tuesday.