Killers who try to cover their tracks by dismembering their victims and scattering the body parts often end up helping investigators narrow their search for suspects, according to a former Toronto homicide detective.

David Perry, a retired police officer and co-CEO of Investigative Solutions Network, a private investigations firm, said the act of dismembering a body is more common in “sexual homicides” than it is in other types of murder.

“Even in a stranger homicide, if someone has dismembered a body it gives you a clue. It tells you that the suspect knows that the police are likely going to be knocking on his or her door at some point,” Perry told CTV’s Canada AM in an interview from Saint John on Tuesday.

“It does take the murder investigation out of context when you have to deal with an outside scene or a scene once a body has been moved. It is more complicated if it has been dismembered and put in different locations. But the evidence will always lead you back to the trail.”

Police in Mississauga, Ont., continue to investigate the death of Hua Guang Liu, whose body parts were discovered in two Toronto-area parks in recent weeks.

Chun Qi Jiang, a former boyfriend, has been charged with second-degree murder in the investigation. He appeared briefly in court on Monday and was remanded into custody.

Despite making their first arrest more than two weeks after the first of Liu’s body parts were discovered, Peel Regional Police investigators were quick to assure the public there was no threat of further attacks.

Perry said the decision to make that announcement was telling about how quickly the police investigation progressed.

“I think they had enough clues and enough evidence at the beginning of the investigation to determine that this was a case that going to be very close to the victim – somebody that was in her very close circle of family and friends,” Perry said. “So there was no apparent danger to the public.”

He added that the recent dismemberment of Lin Jun – whose death and the search for suspect Luka Magnotta made headlines across the globe – also likely played a role in how quickly police reassured the public that there was no threat.

“With the Luka Magnotta news still in everybody’s minds, it probably added to the fear that the community was feeling,” he said.

Perry said killers who dismember their victim help to cover their tracks more often, leave telling clues to help detectives.

“People are unsophisticated in terms of forensic evidence and they think that by dismembering a body and scattering it about it different locations it is going to be more difficult to be detected,” Perry said.

“Most murderers will have quite a psychological episode after a homicide. They panic, they are anxious and they make lots of mistakes. I think that this one of the reasons why we catch so many of them.”