The chief suspect in the 2005 disappearance of Natalee Holloway has pleaded not guilty to charges that he tried to extort the missing teen's mother in exchange for revealing where to find her daughter’s remains. Joran van der Sloot pleaded not guilty Friday in federal court in Birmingham, Alabama. He was extradited this week from Peru, where he's serving a 28-year sentence after confessing to killing a Peruvian woman. Holloway disappeared on the island of Aruba during a high school graduation trip with classmates. She was last seen leaving a bar with van der Sloot. A judge declared her dead, but her body has never been found.