"I did not want to release this picture and I am doing so as a last resort", said Detective-Sergeant Hank Idsinga, lead investigator in the case.
Anyone with information that could help identify the man in the photo is urged to contact Toronto police.
Last month, police confirmed that the remains of Kinsman, Mahmudi, and Navaratnam were found along with the remains of three not yet identified people in garden planters on a property on Mallory Crescent where McArthur stored items for his landscaping business.
CSU has taken the unusual step of unveiling the photo of the unknown deceased person, who, according to investigators, was one of the victims of a serial killer Bruce MacArthur.
Monday, March 5, Idsinga reported that forensic experts have identified: in garden tubs, removed from the site, in fact, was at least seven sets of remains.
CNN reports that McArthur's arrest shocked residents of Toronto's Gay Village who recognized him from bars and shops.
Idsinga said the evidence collected points to a cause of death for some of the men, but wouldn't specify what it was.
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.
Police initially arrested McArthur in early January for the slayings of Selim Esen, 44, who went missing in April, and Andrew Kinsman, 49, who went missing in June.
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He also said five of the six charges laid against the 66-year old are not related to the remains found.
Meanwhile, sources have told the Toronto Sun that the probe has expanded to include missing men, cold cases and unidentified bodies in other jurisdictions.
Investigators also believe there could be more victims.
The remains of Navaratnam, Kinsman and Mahmudi have been identified.
McArthur is charged with first-degree murder in their deaths, as well as the presumed deaths of 44-year-old Selim Esen; Majeed Kayhan, 58; and Dean Lisowick, either 43 or 44.
For years, members of gay community have urged the police to look closely at disappearances of men fearing there was a connection.
And on the accused serial killer's computers, photos of his suspected victims were discovered on the hard drive.
As forensics teams continue to try to identify the remains, Idsinga said police have "just begun" going through historical cold cases to see if there are any links to McArthur. The CBC is saying that the most recently found remains were also at the home at 53 Mallory Cres off of Moore Ave.in Leaside where the first six were found.
Over the past two months, police have searched about 30 properties in Toronto before zeroing in on the eastside residence where upward of 20 planters were seized, and two others it plans to excavate.