Seychelles Mystery: No Illegal Drugs in Hotel Room of Sisters Found Dead on Luxury Trip

The mystery surrounding the deaths of the two sisters found dead in their luxury villa in the Seychelles in late September has deepened as police say no illegal drugs were found in their hotel room, PEOPLE confirms.

While searching their hotel room, “alcohol and different types of medications were taken by police for investigation purposes,” Seychelles police spokesman Jean Toussaint writes to PEOPLE in an email.

On Sept. 22, Robin Marie Korkki, 42, and Annie Marie Korkki, 37, were found lying on top of a bed and unresponsive in their $2,000-a-night luxury villa at the Maia Resort and Spa in the Seychelles, an island nation off the eastern coast of Africa, according to police.

The women’s bodies were cremated on Sept. 30, a spokeswoman for the office of the Seychelles Minister of Travel and Culture tells PEOPLE.

The sisters’ mother and one of their brothers flew to the Seychelles when notified the women had died. “The ashes were given to the family on Saturday morning and they took the ashes with them when they traveled back home on Sunday,” the spokeswoman says.

Authorities are still trying to determine what killed the sisters, who have been described in media reports as outgoing and adventurous.

Toxicology tests are being conducted, but results are not yet ready, says Toussaint.

Autopsy results show that Annie died of acute pulmonary and cerebral edema, while Robin died from acute pulmonary edema, according to a report released by the office of the Seychelles Minister of Travel and Culture.

No visible signs of injuries were found on their bodies, according to the autopsy report.

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Edema is the swelling of tissue brought on by a build-up of fluid. Pulmonary edema restricts the flow of oxygen into the body through the lungs, due to the fluid.

A common cause of pulmonary edema is connected to heart problems, and in its acute form comes on swiftly — though pulmonary edema can also be caused by blood clots, near-drowning, reaction to certain drugs and viral infections, among other causes.

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Cerebral edema, or swelling of the brain, can be caused by physical trauma, infection and strokes.

The two sisters had been staying at the resort since Sept. 15, after being on safari in Africa, according to their Facebook pages.

According to an itinerary found at the hotel, the sisters had already visited Kenya, Tanzania and Zanzibar, police said.

The sisters were found unresponsive in the same bed just two days before they were set to leave the hotel on Sept. 24.

Annie worked at JPMorgan Chase in Denver and Robin was a financial trader in Chicago. They both attended high school in Minnesota.

Hotel staff told authorities they saw the women consuming alcohol throughout the day on Sept. 21, according to police. A butler helped the sisters to their villa around 8:15 p.m., according to police.

The butler returned to the room at around 8:30 a.m. the next day, according to police. When the butler returned at 11 a.m. and didn’t hear any movement inside their room, hotel staff entered the room and found them unresponsive on the same bed, according to the Seychelles News Agency.