DUBAI // The 15 pirates US navy officials say killed four Americans on a yacht could face trial in the United States, a US military spokesman said yesterday.
The military, FBI and Justice Department are working on the next steps for dealing with the pirates, said Bob Prucha, a spokesman for US Central Command (Centcom) in Florida. The 15 are being held on the aircraft carrier USS Enterprise off East Africa.
The pirates will be brought to justice, said Vice Adm Mark Fox, head of Centcom naval forces.
The Fifth Fleet declined to respond to questions, and the FBI was unavailable for comment.
The attackers seized the S/V Quest on Friday and sent two representatives aboard a US warship for negotiations. On Tuesday, a pirate aboard the yacht fired a rocket-propelled grenade at the US ship, and then gunfire was heard from the yacht.
It was unclear what caused the pirates to fire, since negotiations were ongoing and the nearest warship had not made any moves, said another Centcom spokesman, Michael Lawhorn.
The shots prompted naval forces to board the yacht. There they found the hostages - Jean and Scott Adam, Phyllis Macay and Robert Riggle - fatally wounded.
The sailors found two pirates already dead and killed two more. They brought the remaining 13 onto the warship.
The incident came a week after a US court sentenced a Somali pirate, Abduwali Muse, to 34 years in prison for hijacking the Maersk Alabama in 2009. Five more men - convicted last November for attacking a US navy ship in April 2010 - face sentencing next month.
The slain Americans were four adventure seekers who loved the sea. Friends said they were meticulous and planned for any dangers. The Adams, of Marina del Rey, California, owned the boat. Riggle and Macay, who lived in Seattle, had joined them for the trip.
Macay's niece, Nina Crossland, told reporters on Tuesday that her aunt was "a very smart and avid sailor".
"I think she was smart enough and planned ahead and prepared to not be in this type of situation," she said.
The Adams had been sailing full-time on their 18-metre yacht since December 2004, after retiring.
The four sailors travelled with a large flotilla to stay safe earlier in the trip, but left the group at the time of the attack, said Ms Crossland.
Macay and Riggle had left Seattle on Riggle's sailing boat for a voyage in September 2007, but in recent years had been crewing on separate boats, said Cynthia Kirkham, a friend of Macay's who lives in Seattle.
Scott Adam, who was in his mid-60s, had been an associate producer in Hollywood, but then enrolled in Fuller Theological Seminary, in Pasadena, California, a decade ago, said Robert K Johnston, a professor at the seminary. Jean Adam was a dentist.
At St Monica's Catholic Church, where the Adams were parishioners and Jean Adam sang in the choir, Monsignor Lloyd Torgerson described the killings as heartbreaking. The Adams took Bibles with them to distribute around the world, he said.
Riggle had worked as a relief veterinarian for the Seattle Animal Shelter for the past eight years or so, spaying and neutering adopted animals, said the shelter's director, Don Jordan.
"He wasn't a man of many words, but he was a kindhearted individual with a great passion for animals and animal welfare," Mr Jordan said.
Macay was vice president for training and development for Profitability Consulting Group, an adviser to retail furniture stores based in North Carolina. She and Riggle were romantically involved when they first met, but later sailed together as platonic friends.
John Eggers, the chief executive of Profitability Consulting, said Macay was regarded in the industry as one of the top educators and presenters on design and sales.
"She was such a free spirit," Mr Eggers said. "She was just a real professional and loved life."
Somali pirates have during the past year expanded their reach from the Gulf of Aden to the Arabian Sea and much of the Indian Ocean. Most of the hijackings this year - 48 incidents and 11 hijackings for a total of 224 hostages - have occurred in these waters.
Nearly 100 yachts are still travelling through the waters, Captain Lodge said.
"We recommend that if you're not required to be in the area for commercial purposes, that you avoid the region," he said.
The Americans were hijacked off the coast of Oman on their way to Salalah.
* With additional reporting by the Associated Press