The Hallandale Beach Police Department says the man and woman were found Thursday in their condo 30 km north of Miami by a concerned neighbour.
Investigators confirmed the deaths are a double homicide.
"(It's) not natural causes," an officer at the scene told media. "Foul play is suspected."
A neighbour, using a spare key to enter their townhouse in the Venetian Park complex on Northeast 25th Ave., made the grisly discovery around 6:30 p.m. Thursday.
Police have identified the victims as David Pichosky, 71, and Rochelle Wise, 66.
Residents of the quiet complex told the South Florida Sun Sentinel they were stunned by the double murder.
Pichosky, a snowbird for 20 years who was known to his Florida neighbours as Donny, married Wise after his first wife died.
But the ripple effects have been felt even more in Forest Hill, where the couple resided for eight months of the year.
A relative of Pichosky, reached by phone Friday, said the grief-stricken family is asking for privacy.
"We're still trying to absorb everything," said the woman, who did not give her name.
Those who knew the couple at their Toronto home are also trying to come to grips with the killings.
"This is just devastating," George Bergman, their superintendent, said.
He said the seniors had lived in a second-floor apartment at least since he was hired six years ago.
"They were wonderful people," Bergman said.
He said he believed Pichosky was an accountant.
Staff at Bialik Hebrew Day School, up the street from the couple's building, are also mourning the deaths of Wise, their former vice-principal, and her husband.
"Rochelle was an adored member of the community and respected as an outstanding educator and woman of great character and kind spirit," the school said in a statement.
Wise was vice-principal at the elementary school for many years.
"She retired about two and a half years ago," the mother said. "She was a lovely lady."
Investigators remain tight-lipped about the slayings, so how and why they were killed is still a mystery.
The RCMP is co-ordinating with local authorities, as are Canadian consular officials.
"Our thoughts are with the family and friends of the two Canadian citizens who passed away in Florida," Foreign Affairs spokesman Chrystiane Roy said, adding assistance will be offered to their family.