Gatineau police said two high-profile murder cases in their city are not linked to an ongoing Ottawa investigation involving a pattern of violence against sex-trade workers.

Last month Ottawa police chief Vern White warned sex-trade workers about a pattern of violence, asking them to be extra cautious over their safety.

White would not elaborate on the pattern, saying the investigation was in the early stages.

But Ottawa police are actively looking at six unsolved murders of prostitutes dating back more than 20 years.

Most recently, the body of Jennifer Stewart, 36, turned up at a Vanier parking lot in August, 2010, and Leeann Lawson, 23, was found in September this year in a Lower Town parking lot.

Morisseau, LeBlanc cases investigated

Gatineau police said they contacted Ottawa police to see what links could be made between the Ottawa crimes and two cases of their own: the 2006 death of 27-year-old Kelly Morrisseau, who was found dead in a parking lot near Gatineau Park, and the death of Valerie LeBlanc, the 18-year-old CEGEP student found outside her school last year.

Gatineau police Sgt. Pierre Lanthier said his force with the help of the Sureté du Quebec did extensive analysis of the two cases, and also looked at information coming out of Ottawa before determining there were no connections.

"We have expert good police officers, investigators working with those people they are analyzing every element and every detail and [they] arrived at the conclusion they are not related to each other," said Lanthier.

Gatineau police said Morriseau's case has gone cold. But the Leblanc investigation remains a priority, with three full-time investigators assigned to the case.

1,200 tips in LeBlanc case

Police have received more than 1,200 tips in the Leblanc case, and have followed up on about three-quarters of those tips.

Leblanc's body was discovered on Aug. 23 in a forest near CEGEP de l'Outaouais in the Hull sector of Gatineau. She died from severe head trauma and her body was also found burned.

Police still have no suspects in the homicide and are looking for a main witness.

Police are offering a $10,000 reward for information related to the case.