Police have announced charges against a Kingston Penitentiary inmate in connection to the murders of three prostitutes whose bodies were found in Toronto between 1994 and 1997.

Toronto police announced on Thursday that Peter Dale MacDonald, 52, has been charged in the deaths. MacDonald is currently an inmate at Kingston Penitentiary for the 2000 murder of Toronto man James Campbell.

The victim had been a casual sex partner of MacDonald, but the convicted man claimed at his trial he had been provoked into strangling Campbell while they were having sex.

MacDonald is originally from Prince Edward Island, but police believe he was living in Toronto during a period in the 1990s when three women connected to the sex trade industry in the troubled neighbourhood of Parkdale were discovered dead near a pool next to Lake Ontario.

On July 7, 1994, Julieanne Middleton, 23, was found strangled to death near pool on the shore of Lake Ontario, just west of Toronto's downtown.

Virginia Lee Coote, 33, was found dead in the same area on Oct. 28, 1994. Darlene MacNeill, 35, was found strangled near the same pool on Oct. 29, 1997.

Cold case files made available by police describe each woman as being addicted to crack cocaine and funding their addition through involvement in street-level prostitution.

Homicide Det.-Sgt. Steve Ryan said on Thursday that the similarities between the cases led police to launch a special task force. He said that task force recently identified MacDonald as a suspect and had been a person of interest for some time.

"Over the past 16 years and within the last little while we've managed to come up with an extra piece that we needed to charge him," he said.

"If anyone has any information regarding MacDonald back in the days of '94 and '98, we certainly would like to talk to them," Ryan said at the news conference.

MacDonald made an initial court appearance on Thursday. His next appearance isn't yet known.

Earlier this year, MacDonald was charged with the death of a 40-year-old Michelle Charette, of Windsor, dating back to 2000.

Ryan said he would not discuss MacDonald's connection to the Charette murder investigation, nor would he comment on the reason MacDonald was being held at Kingston Penitentiary.

Windsor police have said there is no information to indicate Charette was a sex-trade worker like the Toronto women, but they do believe she was an acquaintance of MacDonald's.

He had been first charged in connection with her death in 2003, but the Crown withdrew the charge following a preliminary hearing due to a lack of evidence.

Windsor police say new evidence allowed them to lay the charge once again.

None of the new allegations against MacDonald have been proven in a court of law.

With files from The Canadian Press