SAN JUAN, Puerto Rico — Authorities in the eastern Caribbean said they were trying to locate two people believed to be U.S. citizens who were aboard a yacht that was hijacked by three escaped prisoners from Grenada.

The Royal Grenada Police Force said in a statement released on Friday that they were working on leads “that suggest” the two occupants of the yacht may have been killed.

“This investigation is in its infancy stage,” police said.

The nonprofit Salty Dawg Sailing Association identified the owners as Ralph Hendry and Kathy Brandel. It said they are “veteran cruisers” and longtime members of the association, calling them “warmhearted and capable.” A relative of Hendry didn’t immediately return a message seeking comment on Saturday.

The association said that a cruising skipper had contacted the association about a member’s yacht, Simplicity, that was found “anchored and abandoned” off a beach on the island of 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 in a statement Thursday.

The association said Hendry and Brandel had sailed the yacht in last year’s Caribbean Rally from Hampton, Virginia, to Antigua, and were spending the winter cruising in the eastern Caribbean.

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

Hendry’s family issued a statement on Saturday thanking police, local coast guards and all those who helped authorities gather information.

“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.

They also asked that all those trying to conduct independent searches to “stand down.”

“The only way we feel this situation could be worse would be if anyone was hurt or endangered trying to conduct searches,” the family said.

Authorities in Grenada said they have dispatched senior investigators and a forensic specialist to the nearby island of St. Vincent, where the escaped prisoners were arrested on Wednesday.

The prisoners, ages 19, 25 and 30, were charged a couple of months ago 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 in Grenada said.

The three men escaped from their holding cell on Feb. 18, according to police.

Authorities said a preliminary investigation suggests that the three men seized the yacht from Grenada’s capital, St. George’s, and traveled to St. Vincent. The owners of the yacht haven’t been identified.