Authorities in the eastern Caribbean are scouring waters in the region in hopes of finding a missing U.S. couple who were aboard their catamaran Simplicity more than a week ago when police say it was hijacked by three escaped prisoners from Grenada.Video above: Son speaks about missing Virginia couple in CaribbeanPolice have said that Ralph Hendry and Kathy Brandel are presumed dead. The search for them began on Feb. 21 after someone discovered their catamaran abandoned on the shores of St. Vincent and alerted authorities.Police say the three prisoners escaped from a police station on Feb. 18 and hijacked the catamaran a day later. Authorities said the prisoners then illegally entered the southwest coast of St. Vincent on Feb. 19 and docked the boat. Two days later, the three men were arrested along the island's northwest coast.Here's what to know about the case:Why was the couple targeted?It's unclear why the escaped prisoners hijacked the couple's catamaran, but it was moored at Grand Anse beach, near the police station where the three men escaped.Police believe the men hijacked the catamaran with the couple aboard and then allegedly threw them into the water while traveling to St. Vincent, which is located north of Grenada.They noted that there were signs of violence aboard the catamaran.Who are the escaped prisoners?Police in Grenada have identified the escaped prisoners as Trevon Robertson, a 19-year-old unemployed man; Abita Stanislaus, a 25-year-old farmer; and Ron Mitchell, a 30-year-old sailor.All 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.Vannie Curwen, Grenada’s assistant police commissioner, has said the men had been placed in a holding cell rather than in jail because a judge hadn't yet ruled whether they would be released on bail.Who is the couple?The Salty Dawg Sailing Association has described Brandel and Hendry as veteran cruisers and longtime members who were “warm-hearted and capable.” It noted that Brandel served on the association’s board for two years.The association said the couple had sailed their boat in the 2023 Caribbean Rally from Hampton, Virginia, to Antigua and planned to spend the winter cruising the eastern Caribbean. A GoFundMe donation page stated that Brandel had become a first-time grandmother.Nick Buro, Brandel’s son, and Bryan Hendry, Hendry’s son, said in a statement Tuesday that they were “incredibly saddened” to hear that the couple was presumed dead, but added that they remain optimistic about the ongoing search.“While the end of their life may have been dark, they brought light, and that light will never be extinguished from the hearts and minds of the people who knew, loved and cared so deeply about them,” they said.Why haven't the prisoners been charged in the case? Police in Grenada and St. Vincent have provided limited information about the case of the missing couple, noting that the investigation is ongoing, though they have said the couple is presumed dead.Authorities haven't yet shared any specific evidence linking the three men to the couple’s disappearance. St. Vincent police say the men have been cooperating in the investigation.The men pleaded guilty this week to immigration-related charges, and are scheduled to be sentenced on those counts in early March.Who has jurisdiction over the case? Authorities haven't said whether prosecutors in St. Vincent or Grenada would pursue the case involving the couple.Grenada Police Commissioner Don McKenzie said the attorney generals and prosecutors on both islands “are in discussions.”Meanwhile, Grenada police sent a team of five officials to help with the investigation in nearby St. Vincent.What's next? Police in Grenada have launched an investigation into how the men were able to escape from their holding cell.McKenzie has said the police station should have been secure enough to prevent such an escape, and that authorities are looking into whether it was a “system failure” or a “slip up.”McKenzie has said no officers have resigned or been disciplined, although one supervisor at the station has been transferred to another location “to ensure a thorough investigation in this matter.”