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.

Watch the previous Dateline report Behind Bars: Joran van der Sloot from Friday, September 10th, 2010.