SAN JUAN, Puerto Rico (AP) — An older U.S. couple whose catamaran was hijacked last week in the Caribbean by three escaped prisoners were presumed dead and likely were thrown into the ocean, police said Monday.

The accounts by police in Grenada and in St. Vincent and the Grenadines were a blow to those who were independently helping search for Ralph Hendry and Kathy Brandel and had hoped they were still alive.

Don McKenzie, police commissioner of the Royal Grenada Police Force, said at a news conference that the three prisoners escaped on Feb. 18 from the South Saint George Police Station. They hijacked the catamaran “Simplicity” on the following day and then headed to St. Vincent, where they were arrested last Wednesday, he said.

“Information suggests that while traveling between Grenada and St Vincent, they disposed of the occupants,” McKenzie said.

McKenzie said he had no conclusive proof that the couple was dead, but cited a “low probability” they were alive.

Hours later, the main spokesman for the Royal St. Vincent and the Grenadines Police Force posted a video saying that while no bodies have been found, the couple is presumed dead based on the investigation so far.

The suspects were being investigated for several criminal acts, including “bodily harm to the couple,” spokesman Junior Simmons said in the brief recorded statement. There were signs of violence on the couple’s boat found abandoned in St. Vincent, he said.

“Several items were strewn on the deck and in the cabin, and a red substance that resembles blood was seen on board,” he said.

The nonprofit Salty Dawg Sailing Association has said that Hendry and Brandel were “veteran cruisers” and longtime members of the association, calling them “warm-hearted and capable.”

It said the couple 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.

A son of Hendry and a son of Brandel did not immediately return messages for comment.

A GoFundMe page created to raise money for the couple’s family noted that Brandel had recently become a first-time grandmother, and that the sailing community was “shattered” by what happened.

“Kathy and Ralph, experienced adventurers, spent their retirement sailing aboard Simplicity, spending summers in New England and embracing the warmth of Caribbean winters,” the page stated.

McKenzie, Grenada’s police commissioner, said a five-person team was sent to St. Vincent to help with the investigation.

After his brief announcement on Monday, McKenzie and other police officials took questions from local media, including one reporter who asked, “Who is really to be blamed for this massive failure to keep these prisoners under the control of the (Royal Grenada Police Force) which has now resulted in this tragedy?”

McKenzie said police have launched an investigation into the escape and are looking into whether it was “a system failure” or a case of a “slip up.”

“All aspects of that investigation are on the table,” he said, adding that the police holding station where the three men were being held has “sufficient safety to prevent an incident like that (from) occurring.”

When the reporter asked why the three men who were arrested remained in a holding cell instead of prison, Vannie Curwen, assistant police commissioner, said the men first had to see a magistrate who would decide whether to grant bail or order them remanded.

The escaped prisoners, Trevon Robertson, a 19-year-old unemployed man; Abita Stanislaus, a 25-year-old farmer; and Ron Mitchell, a 30-year-old sailor; were charged a couple of months ago with one count of robbery with violence. Mitchell 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.

Simmons said the three men appeared in court in St. Vincent on Monday and pleaded guilty to four counts each of immigration-related charges, including entering the island as a “prohibited immigrant” with no passport. They are scheduled to be sentenced on those charges in March.