FORT PIERCE, Fla. — An American couple who went missing while sailing off the coast of Granada is feared dead after their catamaran yacht was hijacked by three escaped prisoners, authorities said.

The Royal Grenada Police Force said in a statement released Thursday that they were working on leads "that suggest" that the two occupants of the yacht — named Simplicity — may have been killed. While details on the incident remain unclear, police said preliminary information indicates that the case is likely tied to the escape of the three prisoners.

"It is believed that the occupants of the yacht were American citizens," police said, adding that the investigation was still in "its infancy stage."

The nonprofit Salty Dawg Sailing Association identified the couple as Kathy Brandel and Ralph Hendry in a statement. The association noted that the pair were veteran cruisers and longtime members of the association, calling them "warmhearted and capable."

"This is a very upsetting event and details are still unconfirmed by the authorities, but this does appear to be a tragic event," Bob Osborn, the association’s president, said in the statement. "In all my years of cruising the Caribbean, I have never heard of anything like this."

Hendry and Brandel were last seen on Feb. 18 and are believed to have been killed the following day near the shores of Grand Anse Beach in Grenada, according to a GoFundMe page raising money for their family. The funds raised will help cover funeral costs and recover the couple's vessel and belongings.

Missing couple's yacht found 'anchored and abandoned'

Hendry and Brandel were on their final voyage with the Salty Dawg Sailing Association when their yacht was found, "bearing chilling evidence of a violent struggle," the GoFundMe page states.

The association said it was alerted by a cruising skipper about a member's yacht, Simplicity, that was found "anchored and abandoned" off a beach on the island of St. Vincent. The association added that its live member’s tracking map showed the vessel anchored in Grenada before it moved to its last anchorage off St. Vincent.

"The good Samaritan had boarded the boat and noted that the owners … were not onboard and found evidence of apparent violence," the association said. The St. Vincent Coast Guard took possession of Simplicity and local police are investigating with the U.S. Embassy and the Grenada police, according to the association.

On Saturday, family members of the couple met with authorities in St. Vincent, where they were seen boarding the vessel — which was being guarded by officials, one of whom was wearing latex gloves.

Hendry's family issued a statement Saturday thanking police, local coast guards, and those who helped authorities gather information. They also asked that all those trying to conduct independent searches "stand down."

"It means so much to us that so many people cared for Ralph and Kathy as friends and fellow cruisers that they are willing to stop and help in whatever way possible," the family said.

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Incident coincided with the escape of prisoners

Authorities in Grenada are investigating what happened to the couple and said they had dispatched senior investigators and a forensic specialist to St. Vincent, where the escaped prisoners were arrested Wednesday.

According to Grenada police, preliminary information suggests that the prisoners hijacked the yacht in St. George’s in Grenada, and traveled to the nearby island of St. Vincent. The three men had escaped from their holding cell on Feb. 18, police said.

The prisoners, ages 19, 25, and 30, were arrested and charged in December with one count of robbery with violence. The eldest inmate also was charged with one count of rape, three counts of attempted rape, and two counts of indecent assault and causing harm, police said.

Couple remembered by family, friends

According to the GoFundMe page, Hendry and Brandel were "seasoned sailors who lived on their beloved catamaran."

The pair spent their retirement sailing, the GoFundMe page states. The couple had sailed their yacht in last year's Caribbean Rally from Hampton, Virginia, to Antigua, and were spending the winter cruising in the eastern Caribbean, the Salty Dawg Sailing Association said.

WPTV-Channel 5 reported that the couple spent their winters docked at a Fort Pierce, Florida, marina, according to Hendry's sister, Suellen Desmaris.

"This was their whole life. They didn't own another home, they didn't own cars, they owned Simplicity," Desmarais told WPTV. "And when you were invited onto Simplicity, you were made to feel as magical as they were and as magical as that boat was."

The couple had previously docked their catamaran at the Safe Harbor Harbortown Marina in Fort Pierce.

"They were the sweetest people," Keith Mallamo said in an email to TCPalm, part of the USA TODAY Network. Mallamo said he was friends with the couple when they docked their vessels at the marina in Fort Pierce.

One Christmas, Brendel baked cookies for everyone on the dock, and Hendry was always available to help his fellow sailors, Mallamo wrote.

Contributing: The Associated Press

Colleen Wixon is the education reporter for TCPalm and Treasure Coast Newspapers. Contact her at [email protected].