(CNN) -- After cruising the high seas for nine days, a young crew of Somali and Yemeni pirates spotted a U.S.-flagged yacht and boarded the vessel unbeknownst to its sleeping passengers in the hopes of cashing in on a big ransom, according to a court statement of facts.
But the February hijacking went awry when the men allegedly opened fire on the yacht's four American passengers amid a standoff with U.S. Navy ships more than 400 miles off the coast of Oman.
On Tuesday, two men involved in the incident pleaded guilty to acts of piracy in a Norfolk, Virginia, federal court.
A 22-year-old man named Said Abdi Fooley said he had been looking for a job and joined the group, carrying a semiautomatic assault rifle during the hijacking, according to the U.S. Attorney's Office in Norfolk.
The other man, Abdi Jama Aqid, said he had hoped to net between $70,000 and $80,000 -- a fortune in Somalia, a poverty-stricken east African country -- for a job that involved spotting potential targets for his pirate crew.
According to court documents, the group's financier was expected to receive 35% of any bounty paid, while the rest of the money would go to the alleged pirates and their interpreter.
Both men are set for sentencing on September 9 and could face life behind bars.
Their plea comes after two other alleged pirates -- Burhan Abdirahman Yusuf and Jilani Abdiali -- pleaded guilty to similar charges Monday.
A total of seven men have pleaded guilty to piracy and hostage-taking in the deadly February 22 incident, though all have denied pulling the trigger or triggers that resulted in the deaths of their American hostages.
The men are among 14 alleged pirates from Somalia and one from Yemen who face charges related to the hijacking and subsequent killing.
In a plea agreement, Yusuf said a person named Ibrahim -- the supposed leader of the group who was killed in the ensuing firefight -- told the pursing U.S. Navy ships, "We are not going to stop; you try to stop us if you can."
Yusuf said that some of the men had discussed killing the captured crew in an effort to compel the U.S. boats to retreat.
He later identified the alleged killers as co-defendants Ahmed Muse Salad, Abukar Osman Beyle and Shani Nurani Shiekh Abrar. Two other gunmen were killed by the Navy during the ensuing fight, according to court documents.
When U.S. forces engaged the hijackers and clambered aboard the vessel, they discovered the bodies of ship owners Jean and Scott Adam and Phyllis Macay and Bob Riggle.
Vice Adm. Mark Fox said the Navy responded after a rocket-propelled grenade was fired at a U.S. Navy ship from about 600 yards away -- and missed -- and the sound of gunfire could be heard on board the yacht.
The incident took place as negotiations involving the FBI were under way for the hostages' release, Fox said.
Two of the alleged pirates were found dead on board the vessel, he said. In the process of clearing the vessel, U.S. forces also killed two others, one with a knife, Fox added.
The incident marks one of the deadliest pirate hijackings involving U.S. citizens in recent memory and comes at a time that the International Maritime Bureau describes as an "all-time high" for pirate attacks.