Questions continue to swirl about the deaths of Barry and Honey Sherman a week after their bodies were found in the basement of their Toronto mansion.

"I think everything in this case raises an eyebrow," said former Toronto homicide detective Dave Perry. "We're dealing with two victims that are very well known and extremely well respected internationally. That adds a whole new twist to it."

Police have released few details about the investigation, fuelling speculation as to the circumstances surrounding the deaths of the Toronto billionaire couple. This is what we know so far.

What police have said

Toronto police have said very little about the case. They confirmed in a news release that at 11:44 a.m. on Friday, Dec. 15, officers responded to a call at 50 Old Colony Road, an upscale address in the Toronto neighbourhood of North York.

Inside the mansion, a real estate agent had discovered the bodies of Barry Sherman, 75, founder of the generic drug giant Apotex, and his wife, Honey, 70.

According to the results of a post-mortem examination, both died as a result of "ligature neck compression." While homicide investigators have taken the lead in the case, it has not been classified as a homicide but, rather, a "suspicious death investigation."

Police secure the Sherman home at 50 Old Colony Rd. in Toronto. (Christopher Katsarov/Canadian Press)

Police said there was no threat to public safety. Brandon Price, a detective with the Toronto homicide squad, said investigators found no signs of "forced entry" into the house, and police were not "currently seeking or looking for an outstanding suspect."

On Tuesday, Toronto police confirmed to CBC News that they "have no evidence to change what we have said."

What police haven't said

Although there have been some media reports about evidence, police have yet to confirm any specifics beyond cause of death. However, CBC News has learned that the Shermans were found by the pool in their basement and that investigators have found no security cameras inside or outside the home.

Police will be doing a forensic analysis to look for possible signs of a struggle, marks indicating someone was dragged or bodily fluids like blood.

"You have to prove, working backwards from where they're found, how they got to where they are," said Perry.

Speculation

There are three main scenarios investigators will consider: a double suicide, a double homicide or a murder-suicide.

The Shermans both died by strangulation, but how that occurred is still unclear.

If they were both found hanged, it's unlikely it was a double suicide, said former Toronto homicide detective Mark Mandelson.

"I think if you canvassed 100 homicide detectives in North America, you'd be hard pressed to find very many of us who said they ever dealt with a double suicide where the mechanism of death was hanging," he said. "I find that sort of the least-palatable resolution."

Flowers from mourners are seen outside the Sherman home, which was recently listed for sale. (Chris Helgren/Reuters)

That means the Shermans could be victims of murder, with an outside actor, or actors, responsible for their deaths.

But Perry said the fact that police are not looking for suspects suggests investigators believe whatever happened to the Shermans was isolated to the house, between the two of them, and no one else was involved.

He said that while investigators must keep their minds wide open, from what police have so far indicated, a double murder is one of the explanations that likely can be excluded.

"It's [a] very unusual, very unusual way to commit homicide," he said. "Where you have this wonderful couple, standing members of the community, are somehow both dead from a ligature compression of the neck. It's bizarre."

Family, friends respond

Earlier this week, in response to media reports suggesting the couple's death may be the result of a murder-suicide, members of the Sherman family lashed out.

In a statement, the Sherman children said their parents' "enthusiasm for life and commitment to ... family and community" was "totally inconsistent" with such a scenario.

"We are shocked and think it's irresponsible that police sources have reportedly advised the media of a theory which neither their family, their friends nor their colleagues believe to be true."

The couple's longtime friend Fred Waks told CBC News he thought it was "impossible" that their deaths could be the result of a murder-suicide.

The founder of Apotex, who was found dead in his Toronto home on Friday, had a major impact on Canadian life both through the pharmaceutical giant he created and for his philanthropic activities. 2:00

Honey Sherman was set to fly to the couple's winter home near Miami on Tuesday while her husband was to join later this week, along with Waks.

One daughter was to be married soon, Waks said, while another had a new baby just a few weeks ago.

The home where their bodies were found was registered to both Shermans and had recently been put on the market for approximately $7 million.

Legal issues

As a producer of more than 300 generic pharmaceutical products, Apotex has been involved in a number of court cases, as drug companies have pushed back on its efforts to sell cheaper no-name options.

Sherman also faced legal action from family members alleging they had been cut out of the company over the years. The Toronto billionaire's orphaned cousins, the Winter siblings, sued Sherman for a cut of his Apotex fortune in 2007. A judge dismissed the case in September as an abuse of process, but court records show the Winters filed an appeal a month later.

Funeral services for the Shermans were held Dec. 21 in the Toronto suburb of Mississauga, Ont., and attended by several thousand people, including Prime Minister Justin Trudeau, Ontario Premier Kathleen Wynne and Toronto Mayor John Tory.