An Ottawa man who killed two wives and a neighbour in three separate crimes over a two-decade period has been sentenced to life in prison with no chance of parole for 25 years.

Camille Cleroux, 58, pleaded guilty in an Ottawa court Tuesday to the first-degree murder of neighbour Paula Leclair and to second-degree murder in the deaths of Jean Rock and Lise Roy.

Camille Cleroux pleaded guilty to first-degree murder and two counts of second-degree murder on Tuesday. (Sketch by Laurie Foster-MacLeod/CBC)

Ontario Superior Court Judge Lynn Ratushny denied a defence request for credit for time already served.

"With a mind that has functioned in a way that yours has and does, there's no better place for you than in custody," Ratushny said in handing down the sentence.

"After hearing the stomach-churning details today, and your plan to kill these cherished women just to get them out of your way, we can all take some comfort knowing that you are incarcerated and likely will be for the rest of your life."

Killed neighbour over apartment

Cleroux was first arrested and charged in 2010 in the death of Leclair, 64, after her body was discovered in a wooded area near where she lived.

He lived in the same apartment building and had taken over her apartment, prompting her son to report her missing.

After the plea, the Crown attorney told the court Cleroux killed Leclair because he wanted her apartment.

"When she refused to let him move in, he killed her," James Cavanagh said.

Cavanagh said Cleroux led LeClair to the site where he had already dug her grave and then stabbed her repeatedly in the back before striking her in the head with a rock.

After he was taken into custody, Cleroux was charged in the deaths of two former wives. Roy disappeared in 1990 and Rock was last seen in 2003. During the course of the investigation, police found human remains at his former home on Heatherington Road in south Ottawa and later at a second site in a forest off Albion Road.

'My heart is broken beyond repair'

Family members delivered victim impact statements in court as part of the sentencing hearing immediately following the plea.

"No loved one should ever have to go through this pain," said Audrey Creelman, Rock's mother.

Jean Rock's stepmother read a statement from Rock's father, who had earlier suffered an apparent seizure in the courtroom.

"Our family is now incomplete and will never be the same," read John Rock's statement. "I welcomed a monster into my home and now I feel sick. My heart is broken beyond repair."

Rock's brother Daniel also gave a victim impact statement, saying "I think about old memories, and my heart breaks when I think we won't create new memories."

Leclair's son also provided a written victim impact statement to the judge.