The police source spoke on the condition of anonymity because they weren't authorized to release information ahead of a news conference later Monday morning.
McArthur, a 66-year-old self-employed landscaper, is now charged with first-degree murder in the deaths of six men who had disappeared from or had ties to Toronto's gay village.
The remains have not been identified.
"I've never done this and I do it with great hesitation", Idsinga said.
Police say this unidentified man is a victim of alleged serial killer Bruce McArthur and have released this photo to the public in the hopes someone will recognize him.
One of the focuses of the investigation has been on human remains found within planters at 53 Mallory Crescent.
December 8, 2017 _ Police Chief Mark Saunders says the force will review its practices in missing persons investigations. All of the six named victims are men, and McArthur had relationships with each of them, some of which were sexual, Toronto Police Service spokeswoman Meaghan Gray said.
"We have technical issues related to decomposition and the effects of post-mortem dismemberment", Pollanen said. They were found in large planters at a home where McArthur did landscaping work and stored items, authorities previously revealed.
The seventh set of remains have yet to be identified and it is not yet known if they are linked to any of the missing men from earlier police investigations, said the source.
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So far, it appears all of the remains have been found at the property on Mallory Crescent.
February 23, 2018 _ Police lay a sixth charge of first-degree murder against McArthur, identify Navaratnam as one of the alleged victims whose remains were found in the planters.
The other three victims have not been officially identified but are presumed dead, the outlet reports.
McArthur is also charged with the murders of 58-year-old Majeed Kayhan, 47-year-old Dean Lisowick, and 44-year-old Selim Esen.
They have now also turned to DNA analysis.
Examiners have also not yet determined cause of death on numerous victims, with decomposition severely hampering their ability to get a complete picture.
Navaratnam was one of three men included in a Toronto police task force dubbed Project Houston looking into a string of disappearances of men from 2010 to 2012 from in and around the city's Gay Village.
A picture of an what investigators believe is an unidentified victim was also released. He did not personally know McArthur, but he knew people who did. Police said they plan to return to the sites with cadaver sniffer dogs to comb for more possible remains once the frozen ground thaws.
McArthur, who once worked as a mall Santa Claus, has pleaded not guilty to the six counts of murder and is due back in court on March 14.