The person who killed Orangeville nurse Sonia Varaschin in her home last summer is likely a man who was familiar with the area where he disposed of her body, police said Thursday.

Police investigating Varaschin's murder say they have consulted with criminal profilers and top homicide investigators from Ontario and the FBI to paint a more detailed picture of her killer than has previously been revealed.

OPP Det.-Insp. Mark Pritchard told reporters Thursday that it is believed that the killer is a man who is "very familiar" with the Orangeville area and the specific location where Varaschin's body was left, a rural area about 12 kilometres outside of the town.

"The location where Sonia's body was found is an area where the offender may be comfortable with and is likely known to him whether as a result of recreation, occupation or illegal activities," Pritchard told reporters at an Orangeville news conference on Thursday morning.

In the days following Varaschin's murder, police believe that her killer may have exhibited key behaviours that his friends, family, associates or co-workers would have noticed.

"These behaviours may include things like unexplained absences from his work and his usual activities, whether work, school or missed appointments," Pritchard said.

"There may have been an increase in his alcohol or drug use and he may have been seen as being irritable, agitated and anxious. This person may also have moved from the area shortly after the occurrence or limited his social interactions to avoid detection."

Police came to these conclusions during a three-day conference on the case, where OPP investigators worked with homicide detectives from Ottawa, Toronto and York Region, as well as criminal profilers from the RCMP and FBI.

Investigators chose to consult these sources, in part because "in Canada this type of crime is very unusual, it rarely happens," Pritchard said.

The victim's mother, Michelle Varaschin, told reporters Thursday that her family is now deeply grieving the loss of Sonia as they prepare to celebrate their first Christmas without her.

"There is nothing that can describe the pain we feel and nothing will ever fill the void that many of us are feeling at this moment," she said at the news conference.

Her family is urging those with information about the case to come forward to police with what they know.

At the news conference, Pritchard further described the unidentified killer as someone willing to take dangerous risks and commit murderous acts.

"I'd say he's a cold-blooded killer," Pritchard said. "He killed somebody who we consider a very low-risk victim and engaged in some very high-risk behaviours."

Pritchard listed those behaviours as entering a home, killing Varaschin, placing the victim's body in her own car, using that car to dispose of the body and then driving back "almost to the scene of the murder, this time with blood clearly visible on the outside of the car to anybody who saw it."

Orangeville is a town of nearly 28,000 that is located about 80 kilometres northwest of Toronto. Varaschin lived in a townhouse near the local highway that leads into the town.

Varaschin was reported missing in late August, when she failed to show up for work. Within hours, police found her blood-spattered car abandoned near her Orangeville home with no trace of the missing 42-year-old woman.

Days later, Varaschin's body was found by a person walking their dog in a rural area outside of Orangeville. Her death was ruled as a homicide.

Police later said that they believed Varaschin may have known her killer.

At the news conference on Thursday, Pritchard said it is also possible that the killer thought he knew his victim.

"She may have known the killer or the killer may have known her. The connection might be in his mind that he knew her, but perhaps she did not know him," he said.

Police have also previously revealed that the person responsible for Varaschin's killing wore boots sold exclusively through the Mark's Work Wearhouse chain of clothing stores.

Yet, despite some 460 tips from the public and 500 interviews, police have still not been able to catch Varaschin's killer.

Pritchard said a key tip from someone with information could help break the case open.

"Someone familiar with the killer may recognize these traits and we are appealing to that individual -- or these people -- to come forward and call the police immediately," he said.

Orangeville Police Chief Joseph Tomei said his force is urging the public to exercise safety when in public or in their homes while this case remains unsolved.