Philippine government prosecutors charged a U.S. Marine with murder Monday in the killing of a Filipino, saying the suspect acknowledged attacking the victim after he found out she was a transgender woman.

Prosecutor Emilie de los Santos said there was "probable cause" that Marine Pfc. Joseph Scott Pemberton, who has been detained since shortly after the October incident, killed Jennifer Laude, whose former name was Jeffrey, in the motel room where the victim's body was found in Olongapo city, northwest of Manila. She had apparently been strangled and drowned in a toilet bowl.

"It's murder," de los Santos told reporters after filing the charge against the 19-year-old Pemberton before a regional court. "It was aggravated by treachery, abuse of superior strength and cruelty."

Among the evidence submitted by de los Santos and other prosecutors were statements by Pemberton's three Marine colleagues who went bar-hopping with him on Oct. 11 in Olongapo, a former liberty town when the U.S. Navy was at the vast Subic Naval base, now a bustling commercial Freeport and recreation hub.

Pemberton and some of his colleagues later picked up women at a disco bar and separately checked in at nearby motels, then returned to their ship after midnight. Witnesses saw Pemberton check in with Laude at a motel room, where he was seen leaving shortly before the discovery of the killing, prosecutors said in their statement to the court.

Marine Lance Corporal Jairn Michael Rose, who went out with Pemberton that night, acknowledged that the suspect later confided back at their ship that he attacked the woman he was with by choking her after discovering that she was a transgender when she undressed, according to the prosecutors.

"I think I killed a he/she," Pemberton was quoted as having told Rose.

Pemberton, a skilled boxer, allegedly said he choked her from behind with his arm "for a couple of minutes" until she stopped moving then dragged her into the bathroom, according to the prosecutors.

The new details are likely to spark renewed condemnation by left-wing and transgender groups, which have labeled the attack a hate crime.

The case comes after the Philippines and the United States strengthened ties with the recent signing of a defense accord that allows greater U.S. access to Philippine military camps. The accord will help Washington's bid to reassert its presence in Asia, and enable Manila to deter what it calls China's aggressive moves to reinforce its claims in disputed South China Sea territories.

The case reignited a debate over custody of American military personnel accused of crimes. But the looming irritant between the treaty allies over Pemberton's custody was eased after Washington agreed to move him from a U.S. warship to the Philippine military's main camp in metropolitan Manila, where he remained under American custody with an outer ring of Filipino guards.

The Philippine government said in a statement issued by its foreign affairs department that it looks "forward to the full cooperation of the U.S. government in ensuring that justice is secured for Laude."

Harry Roque, the lawyer of Laude's family, welcomed the prosecutors' ruling and angrily demanded that Pemberton be thrown into an ordinary jail.