Four Americans aboard a hijacked yacht off the coast of Somalia were killed by their pirate captors Tuesday, touching off a firefight with a U.S. warship, military officials said.
The Americans were sailing the world on a Christian mission to distribute bibles when they were ambushed Feb. 18 by pirates in dangerous waters nearly 300 miles off the Somali coast. On board the yacht were Jean and Scot Adam from California and Phyllis MacKay and Bob Riggle from Washington state.
U.S. forces and at least one Navy warship that had been tracking the yacht for three days and negotiating with the captors responded to gunfire at approximately 1 a.m. ET Tuesday morning.
American military forces killed two pirates aboard the vessel when they responded to gunfire that was believed to have killed the American yachters. The American forces captured 13 pirates and found the remains of two additional pirates. It is now believed that 19 pirates were involved in the kidnapping.
Nina Crossland, a niece of Phyllis MacKay, said today at a news conference that she had been told her aunt was wounded but alive when the U.S. military boarded the Quest, but died shortly after. Officials have confirmed that two of the Americans onboard the Quest were still alive when the military found them.
"It's a shock," Crossland said. "My family is trying to come together to deal with this tragedy."
Crossland said her aunt was merely a sailor on the boat and was not involved with passing out Bibles. The Adams were known to carry and distribute Bibles along their journeys, according to reports.
U.S. forces responded to a rapidly deteriorating situation onboard the Quest and thought immediate action was necessary to save the lives of the hostages, authorities said. The pirates fired an RPG at the USS Sterett, the American ship most closely monitoring the yacht. At the time the first shot were heard on board the Quest, the Americans were negotiating with the pirates and had two of them onboard the Sterett.
It was unclear what the negotiations covered, but a military official said the pirates were attempting to make their way back to the Somali coast. According to one official, the killings of the Americans onboard came as a surprise since the pirates' demeanor had been described as "calm."
A military official said small arms fire was detected by the US forces on the yacht and that it was not directed at the USS Sterett.
It was only after the gunfire was detected, according to the military official, that U.S. special ops forces boarded the Quest and engaged the pirates. Until weapons were fired at the Quest , U.S. forces did not assault the yacht, according to the official.
A timeline released today noted that one of the two pirates killed by special operations forces below deck was killed by a knife. The other was shot.
"As [U.S. Forces] responded to the gunfire, reaching and boarding the Quest, the forces discovered all four hostages had been shot by their captors. Despite immediate steps to provide life-saving care, all four hostages ultimately died of their wounds," according to a statement released by U.S. Central Command in Tampa, Florida.
"We express our deepest condolences for the innocent lives callously lost aboard the Quest," said Gen James N. Mattis, U.S. Central Command commander.
U.S. ships in the area engaged in monitoring the yacht included the aircraft carrier USS Enterprise, the guided-missile cruiser USS Leyte Gulf, the guided-missile destroyers USS Sterett and USS Bulkeley. The ships are deployed to the region to conduct maritime security operations and to provide support to operations Enduring Freedom and New Dawn.
The 58-foot S/V Quest is owned by Jean and Scott Adam, who had been sailing the boat around the world for the past seven years. As they approached the notoriously hostile waters off the Horn of Africa, the Adams cut back using their radios and satellite systems so their location couldn't be tracked by pirates, but they were still found.
The Adams were members of the Del Rey Yacht Club in Marina Del Rey, Calif. The couple had been detailing their travels on a website, where an entry from last December listed their expected stops in 2011 as "Galle, Sri Lanka; Cochin, India; Salalah, Oman; Djibouti, Djibouti; The Suez Canal; and Crete. That gets us to April."
That path would have taken them directly into the pirate-infested waters off the coast of Somalia. Pirates there have seized oceangoing vessels for large ransoms; just last week two supertankers carrying oil were seized in waters far off the Somali coast.
MacKay and Riggle were on an extended leave from their lives in Washington and a friend said Monday he was surprised to learn they were on the Adam's boat since they had their own boat too. The couples had apparently linked up in India, according to her friend John Eggers, who appeared Monday on "Good Morning America," before the shooting.
"What I heard is that they hooked up I guess in India, and they joined the Adams, which is pretty common in the sailing industry I guess. People hook up on boats and take off," said MacKay's friend, John Eggers.
"Phyllis has been sailing for quite a few years. She's been on leave now for about three years. She called one night and said she was going to go on sabbatical, said she'd be back in a year, year and a half, and now it's going on three years," said Eggers. "It was a surprise but she is a very independent, very strong woman. She was at the peak of her career in our industry so it was surprising to me and she was just very respected but she wanted to go on this leave with Bob and away she went."
The last time pirates targeted an American vessel - the Maersk Alabama in 2009 - the heist ended with all but one of the pirates killed by US navy sharp-shooters.
The challenge for international warships now is keeping the pirates from making it to the Somali shore where they and their hostages can easily disappear.
Pirates held British couple Paul and Rachel Chandler for 388 days until they were paid a ransom believed to be above $1 million.
It is believed that Somali pirates currently have 29 ships in their possession and are holding 660 crewmembers hostage.
Pirate seizures have continued in the waters off East Africa despite the constant patrols of by the world's navies, including ships from the United States.
Last Thursday, Abdiwali Abdiqadir Muse was sentenced in New York to 33 years in prison for kidnapping and brutalizing Capt. Richard Phillips, who was held hostage for five days in 2009 when pirates armed with AK-47s scrambled up the stern of Maersk Alabama.
The U.S. Fifth Fleet, based in Bahrain, coordinates an international task force that patrols the waters of East Africa. The European Community also maintains a separate anti-piracy mission in the same waters.
ABC News' Dana Hughes, Steven Portnoy, Kevin Dolak, Luis Martinez and Jeremy Hubbard and Z. Byron Wolf contributed to this report.