Investigators begin piecing together 'puzzle' in Toronto serial killer case

The caseof a suspected serial killer in Toronto has investigators using the tools of archeologistsin their huntfor evidence.

Earlier this week, police discovered dismembered remains of at least three people in the bottoms of large planters aftersearching a property at Mallory Crescent in midtown Toronto. They believe those cases are connected to the presumed deaths of two men who went missing from downtown Toronto.

Bruce McArthur, 66, has been charged with fivecounts of first-degree murder in the deaths ofSelimEsen, 44,Andrew Kinsman 49, Majeed Kayhan, 58,Soroush Mahmudi, 50, and Dean Lisowick, 47. None of the charges hasbeen provedin court.

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Forensic identificationofficers from the Toronto policealong with forensic anthropologists are searching properties acrossthe Greater Toronto Area, looking for evidence.

That evidence could include body parts and decomposed remainsthat would besent to and analyzed at the Ontario Forensic Pathology Service.

Wade Knaap, a forensic identification instructor at the Universityof Toronto's forensic science program, said items would also be examined for potential DNA evidence whilebloodstains could be potentially swabbed for identifying DNA profilesat theCentre ofForensic Sciences.

Meanwhile, investigators will look forfingerprints. Abloodstain pattern analyst can examine anypossible bloodstain patternsto determine what, if any,weaponsor tools were used, the minimum number of blows against a victim and distance from a blood source, Knapp said.

An analyst may also be able to figure out movement of people and objects during and after bloodshed, number of persons involved, position of the victim and the sequence of events, he said.

CBCNews has learned that two other Toronto-area properties have been searched and planters have been seized from both locations.

Dismembered skeletal remains of at least three victims were found in two of the planters from the MalloryCrescent address that were examinedat the Centre of Forensic Sciences.

Among the things police will be looking for are possible burial locations, which might be evident from layers of soil that havebeen moved or lookout of place, saidScottFairgrieve, a Laurentian University professor inthe department of forensic science.Investigators could also use ground-penetrating radar.

Cadaver dogs have been used but arehaving problemsdetecting scents because of the cold weather and frozen ground, a police source told CBC News.

Forensic identificationofficers will piece together a 3D reconstruction of each sitein which they will map out any items found at the scenes.

"You have to be able to identify what was found where, and what items are found next to what other items," said MyriamNafte,a forensic anthropologist who consults oncriminal cases in the U.S. and Canadabut is not involved in this case.

'Putting the pieces of the puzzle together'

With 3D technology, investigators can try to understandthe perpetrator's movements based onwhere items are located on the sceneand which items are relevantto the investigation,Naftesaid.

"It's more about putting the pieces of the puzzle together so if you can see a 3D picture, that's going to be a lot more effective."

The cold weatherwill make the task more challenging, said Fairgrieve.

"Having undertaken these cases myself in very cold weather, you have to put tents overthesescenes and then you havehave to heat them in order tomelt the groundin order to be able to excavate," he said.

As with any excavationorany work on a crime scene, gathering evidence is inherently a "destructive process," he said. Investigators willhave to be cautious not to disturb or damage any evidence.

"So you have to do it in a systematic fashion," he said."It'sgoing to be a lot of hand work."

That means using trowels to dig and collect remains. If they find bones, they will likely shift to wooden instruments such as tongue depressorsto avoid scratching.

"It is like an archeological dig,"said Mary AnneKatzenberg, a forensic anthropologist at the University of Calgary. First, investigators can use heavy equipment to reach certain depths in the soil before switching to precise tools."But once you get down to a level whereyou think you're going to find things, sometimes you'reusing dental instruments and little picks and paintbrushes."

Forensic anthropologists will then have to identifyanydecomposed remains discovered.

Bones help builda profile

"The forensic anthropologist usually builds a profile of what we refer to as anosteobiography," said Fairgrieve."And that's essentially from the bones of the body, being able to tell the vital statistics about an individual such as their age and sex."

Skulls, long bones, pelvic bones andteeth would be compared with what's known aspre-mortemdental and medical records,trying toessentiallyreconstruct who the person was, said Nafte. They will also compare the records with those of anyknownvictims to see if there's a match.

However, a cause of death cannot be established by analyzing just bones. A victim can die with very little trauma evident on their bones, Nafte said, or cansustain a lot of damage and injury to their bones but not die from that.

But if there are dismembered remains withflesh intact,investigators can look for evidence ofgunshotor stabbing wounds, or other kinds of soft tissue trauma thatcould indicate what happenedto thebody prior to orduring death, she said.

By analyzing soil samples, anthropologistscan also determine ifthe bodyhas been moved from another location.

Discovery of insect activity in soft tissuecan also provide clues, like a timeline. A victim that waskilledandburied in June or July would have evidence of maggot infestation, Nafte said.

"The scope is going to be rather wide because you have identifications that have to take place, and you also have to then rebuild exactly what sort of scenario brought a person into this context, the victims," said Fairgrieve. "Theywould look at thevictimologyhow did this person become a victim?"