A pathologist is slated to conduct autopsies Monday, Royal Bahamas Police Force Commissioner Paul Rolle said. Foul play is not suspected in Friday's deaths, Bahamian acting Prime Minister Chester Cooper has said.
Authorities are working on plans to repatriate the bodies of the deceased, and arrangements have been made to hand over their belongings to their representatives in the United States, Rolle said.
Forensic scientists are collecting samples from the deceased, and a lab in Philadelphia is helping with toxicology examinations, Rolle said. The lab expects results will be ready within seven days, he said. Scientists also collected samples from the victims' rooms to check for contaminants, he said.
Officials declined to say whether any contaminants have been found in samples so far. Pathologists will provide an official report once the tests are complete, Rolle said.
Michael Phillips, 68, and his wife Robbie Phillips, 65, from Tennessee were declared dead at the resort Friday, as was Vincent Paul Chiarella, 64, of Florida, who was found unresponsive in a separate room, police said.
A fourth American -- Chiarella's 65-year-old wife, Donnis Chiarella -- was found with her husband. She was airlifted to a hospital in the Bahamian capital before being transferred to Miami's Kendall Hospital, where her condition was upgraded from serious to fair, said Jennifer Guerrieri, a spokesperson for Hospital Corporation of America's east Florida division.
Their son, Austin Chiarella, told ABC News his mother "woke up and my dad was laying there on the floor, and she couldn't move. Her legs and arms was swollen and she couldn't move and she screamed to get someone to come in the door."
Donnis Chiarella told her son she became ill Thursday but after she was released from a clinic, she "thought she was alright," according to ABC.
He said he was heartbroken over his father's death. "My dad was everything to me," he told ABC.
CNN's efforts to reach Austin Chiarella have been unsuccessful.
Victims went to doctor night before
All four victims sought medical treatment before they were found in their rooms, the police commissioner said. They had eaten at different restaurants, he added.
"They were seen by the doctor the night before, and that would have been around 11, and they were discovered the next morning. So, we have the timeline ... between 11 p.m. and 8:30 to 9 a.m.," Rolle said.
The three deaths at Sandals Emerald Bay resort on Great Exuma were also confirmed by Sandals spokeswoman Stacy Royal and the US State Department.
"We are closely monitoring local authorities' investigation into the cause of death. We stand ready to provide all appropriate consular assistance," the State Department said in a news release. "Out of respect for the privacy of the families, we have nothing further to add at this time."
Guests found unresponsive in resort villas
Resort staff alerted police shortly after 9 a.m. Friday that an unresponsive man had been found in a villa, police said. En route to the scene, police were told another man and woman were found unresponsive in another villa, the release said.
Police found in the first villa a "Caucasian male lying on the ground unresponsive" with no signs of trauma. A doctor pronounced him dead, police said. The woman who was hospitalized was found with him, Rolle said Saturday.
At the second villa, they found a second man "slumped against a wall in a bathroom unresponsive," and the woman was "found in a bedroom on a bed," the statement said.
"Both showed signs of convulsion," the release said. Neither showed signs of trauma. They were also pronounced dead by a doctor.
Cooper on Friday asked the nation's health and wellness minister to lead a delegation of health, environment and public works officials to the Exuma district. The Department of Environmental Health Services remained on the scene Monday, Rolle said.
"Nothing is more important to Sandals Resorts than the safety of our guests," the resort said in a statement, adding it is actively working to "support both the investigation as well as the guests' families in every way possible."
Sandals cannot disclose further information "out of respect for the privacy of our guests," it said.
CNN's Carlos Suarez, Eliott C. McLaughlin, Steve Almasy, Hira Humayun, Jason Hanna, Rebekah Riess, Sarah Jorgensen and Susannah Cullinane contributed to this report.