Joran van der Sloot pleaded guilty to murder Wednesday in the 2010 killing of a 21-year-old Peruvian woman.
Van der Sloot, who was arrested but not charged in the 2005 disappearance of 19-year-old Natalee Holloway on the Dutch Caribbean island of Aruba, admitted killing Stephany Flores in his Lima hotel room on May 30, 2010, after the two left a casino together.
"Yes, I want to plead guilty. I wanted from the first moment to confess sincerely," he told the court. "I truly am sorry for this act. I feel very bad."
The three-judge panel said sentencing would be Friday. Van der Sloot faces up to 30 years in prison for slaying Flores, though the guilty verdict was aimed at winning a lighter sentence.
Flores was killed five years to the day after the disappearance of Holloway, an Alabama woman who was celebrating her high school graduation in Aruba and was seen leaving a nightclub with van der Sloot. Her body has never been found.
Van der Sloot was arrested twice in the Holloway case but he was never charged due to a lack of evidence. Holloway's family has criticized Dutch authorities for not making more progress in the case.
'Extreme psychological trauma'
Van der Sloot's lawyer argued after his client's brief statement that the 24-year-old Dutch citizen killed Flores as a result of "extreme psychological trauma" he suffered from the fallout of Holloway's disappearance.
Van der Sloot smiled and appeared relaxed on Wednesday as he chatted with his lawyer after the judges suspended the trial until Friday.
Van der Sloot said January 6 that he would "sincerely confess" to killing Flores in a plea strategy aimed at reducing his eventual prison sentence.
Under Peruvian law, a prison sentence for a "sincere confession" to a murder is normally much shorter than one for an outright guilty plea. He could spend less than a decade behind bars.
Prosecutors have said van der Sloot robbed and killed Flores before fleeing the scene of a crime to Chile.
The defense had complained that the panel of three judges is made up exclusively of women and might be biased against him.
Van der Sloot has told police he strangled Flores, a skilled poker player and the daughter of a wealthy businessman, after he found her looking at his laptop computer in his hotel room.
The laptop contained emails about Holloway's death.
Van der Sloot was arrested in Chile before being returned to Peru for questioning.