NEW YORK (CNN) -- A Somali suspect in the hijacking of the U.S.-flagged Maersk Alabama has been charged with piracy, a count that carries a minimum life sentence.
Abduwali Abdukhadir Muse arrives in the United States on Monday. He was charged with piracy Tuesday.
Abduwali Abdukhadir Muse also has been charged with conspiracy to seize a ship by force, conspiracy to commit hostage-taking and two firearm charges, according to a criminal complaint released by the U.S. attorney's office in the southern district of New York.
Muse "conducted himself as the leader" of the pirates who allegedly took over the Maersk Alabama, according to the criminal complaint.
A federal judge ruled Tuesday that Muse could be tried as an adult.
U.S. Magistrate Judge Andrew Peck had ordered the media and public out of the courtroom earlier while he evaluated Muse's age.
Muse's father in Somalia told defense attorneys the young man was born on November 20, 1993 -- making him 15, the defense attorneys said.
However, the prosecution argued otherwise, saying Muse made statements that suggest he is older.
Before Peck closed the courtroom, Muse wiped his hand over his face at one point, and it appeared he was crying. He had worn a broad smile late Monday when he arrived in New York escorted by a phalanx of law enforcement officers. See timeline of events that led to piracy case »
Muse was arrested in the hijacking of the Maersk Alabama, a cargo ship that pirates attacked on April 8 about 350 miles off the Somali coast. See an interactive map of 2009 pirate attacks off the Horn of Africa »
Peck read the young man his rights and said attorneys had been appointed to represent him because the suspect did not have the resources to hire representation himself.
Muse said through an interpreter that he understood and said, "I don't have any money."
Pirates attacked the Maersk Alabama, a cargo ship, on April 8 about 350 miles off the Somali coast.
According to the criminal complaint, two of the 20 crew members -- all Americans -- saw lights heading toward the Maersk Alabama around 4:30 a.m. on April 8, while the ship was in the Indian Ocean.
After a "brief time," the lights disappeared, the complaint said, but about two hours later, the same crew members saw a small boat approaching and later heard "what sounded like" gunshots, the complaint said.
Crew Member 1 then heard the ship's captain -- later identified as Capt. Richard Phillips -- on the radio saying that two pirates were on the ship's bridge. A third crew member, Crew Member 3, also heard the radio message and began shutting down the ship's power, the complaint said.
The complaint said Muse, who was carrying a gun, was the first alleged pirate on the ship, and said the attackers used a portable ladder to climb on board.
According to the complaint, Muse had fired his gun at Phillips, the captain said, and then took $30,000 from the ship's safe after he forced Phillips to open it. Watch Muse being hauled into court »
Muse demanded that the Maersk Alabama be stopped and that the crew give him the number of the ship's owner, the complaint said.
The captain then ordered the crew to the bridge after Muse ordered him to do so, the complaint said, citing Crew Member 2.
Muse then began canvassing the dark ship with Crew Member 2 as a guide, the complaint said. While they were going through the ship, Crew Member 3, who had not come to the bridge, tackled Muse to the ground, the complaint said. Crew Member 2 helped subdue Muse, and the two tied the young man's hands with wire and took him to the ship's safe room, where several crew members were hiding.
After several hours, the remaining pirates said they would leave the ship if Muse was returned to them, and if a lifeboat was given to them.
Phillips boarded the lifeboat with them and the ship's crew freed Muse, who then boarded the lifeboat, according to the criminal complaint.
The boat floated a short distance from the Maersk, even as the Navy's USS Bainbridge arrived the next day.
Over the next three days, officers on the Bainbridge communicated with the pirates by radio. "In those communications, the pirates threatened to kill the captain if they were not provided with safe passage away from the scene," the complaint said.
At one point, Phillips tried to escape and the pirates shot at him, the complaint said.
On April 12, Muse boarded the USS Bainbridge and demanded safe passage for himself and the other pirates in exchange for Phillips' release. Muse also received medical treatment while he was on the warship, the complaint said.
While Muse was away from the lifeboat, Navy SEALs shot and killed the three remaining pirates.
The U.S. Navy recovered two loaded AK-47 assault rifles; two gunstraps, each containing three AK-47 magazines; one handgun magazine; and multiple cell phones and handheld radios from the lifeboat, according to the complaint.
CNN's Deb Feyerick contributed to this report.