McArthur was charged earlier this month with first-degree murder in the presumed deaths of Selim Esen and Andrew Kinsman, both reported missing from Toronto's gay village area at separate times previous year.
But police said only Kayhan is connected to Project Houston, the force's investigation into three men who disappeared from Toronto's Gay Village between 2010 and 2012.
Idsinga said police had found bodies hidden at the bottom of large planters at multiple addresses, and believed there were more victims than the five people identified so far.
He said police have set up heaters on the property where the excavation work will take place to keep the ground from freezing.
McArthur, 66, was arrested and charged January 18 in the presumed deaths of Selim Esen, 44, and 49-year-old Andrew Kinsman.
"So we've seized quite a few planters from around the city and we'll continue to do that".
Idsinga has said McArthur had a sexual relationship with Kinsman. He said the remains have not been identified.
A witness named Peter Sgromo told The Globe that he had spoken to police after McArthur's arrest. "In whatever way this has affected you, you are not alone", said Rev. Jeff Rock, MCC Toronto's senior pastor, in the release.
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The filing cabinets in question were sold off especially cheaply, because they were clearly full, and no-one could find the keys. Australian Cabinet documents are normally sealed and kept confidential until they are released to the public 20 years later.
McArthur is now being referred to as an alleged serial killer, police said. "There are at least two sites that we do want to excavate where people might be buried".
Another homeowner, who lives near Yonge Street and St Clair Avenue West area, said he hired McArthur to maintain his flower pots when he and his wife bought their townhouse six years ago. Police are searching as many as 30 residences where McArthur worked.
On Jan. 18, McArthur was arrested for Esen's and Kinsman's murders and on the same day the police arrived at Karen Fraser and her husband's home with a warrant telling them to evacuate the premises.
Authorities believe the man went to McArthur's pad to have sex with him, CBC reported.
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The good news is that 80 percent of cardiovascular diseases may be preventable with education and lifestyle changes. Volunteers with the organization say their ultimate goal is to let people know about the silent killer.
"He had wonderful clients and he was kind and generous to them", said Fraser on As It Happens, describing McArthur as a "cheerful, kind grandfather", who would make her laugh with stories about demanding clients.