Tributes have begun pouring in for Barry Sherman, founder of the pharmaceutical company Apotex, and his wife, Honey, after they were found in their Toronto home. A police detective, Brandon Price, described the deaths only as "suspicious".
Mr Sherman founded generic drugmaker Apotex in 1974, then built it into one of the world's largest pharmaceutical makers.
Toronto Mayor John Tory said in statement he was "shocked and heartbroken" to learn of the deaths, noting that the couple had made extensive contributions to the city.
Canadian Prime Minister Justin Trudeau extended his condolences "to their family and friends, and to everyone touched by their vision and spirit".
Mr Sherman, 75, was a prominent donor to Canada's ruling Liberal Party, drawing on a fortune that Forbes estimated at $US3.2 billion ($A4.5 billion).
Hopkinson said police were called to the Shermans' home in an upscale neighbourhood of north Toronto just before noon on Friday in response to a "medical complaint".
"The circumstances of their death appear suspicious, and we are treating it that way", Constable David Hopkinson told the Associated Press at a news conference held outside the couple's home.
The Shermans recently listed their home for sale for almost C$7 million ($5.4 million).
The paper also said that the bodies were "found hanging side by side next to their indoor pool", something that other Canadian outlets later repeated, citing police sources. Honey Sherman was a board member of several institutions: York University, the Baycrest Foundation and Mount Sinai Hospital.
The Sherman family released a statement Saturday saying: "We urge the Toronto Police Service to conduct a thorough, intensive and objective criminal investigation, and urge the media to refrain from further reporting as to the cause of these tragic deaths until the investigation is completed".
Eric Hoskins, Ontario's Minister of Health and Long-Term Care said he was saddened "beyond words".
The couple were well known philanthropists and active on the political scene. Neighbours confirmed that the property was the couple's home. Wonderful human beings, incredible philanthropists, great leaders in healthcare.
"Today I am gutted by the loss of Honey and Barry Sherman". The company undercut name-brand drugs by producing cheaper generic versions.
A University of Toronto website lists the Apotex Foundation and the Shermans as donors in the range of $10 million to $25 million during 1995 and 2003. Sherman and his wife have four children together. They also donated roughly $50 million to the United Jewish Appeal.
"At this point we are not now seeking a suspect", Toronto police homicide Det.