MIAMI (AP) — A 16-year-old boy has been charged with murder and aggravated sexual abuse in Florida in the death of his 18-year-old stepsister on a Carnival Cruise ship, the U.S. Justice Department said. The teen, identified by the government as T.H., was initially charged as a juvenile on Feb. 2, but the case was sealed until U.S. District Judge Beth Bloom said that he would be prosecuted as an adult at the request of prosecutors. Court records show his defense lawyers did not object. An email and voicemail seeking comment from T.H.'s attorneys about the indictment were not immediately returned. Anna Kepner had been traveling on the Carnival Horizon ship in November with her family. Before the ship was scheduled to return to Florida, her body was found concealed under a bed in a room she was sharing with two other teens, including the younger stepbrother. The cause of Kepner’s Nov. 6 death was determined to be mechanical asphyxia, which is when an object or physical force stops someone from breathing. Kepner was a high school cheerleader at Temple Christian School in Titusville, Florida, about 40 miles east of Orlando. At her memorial service in November, family members encouraged people to wear bright colors instead of the traditional black “in honor of Anna’s bright and beautiful soul.” Teens prosecuted in federal court are rare. T.H. was seen at the Miami courthouse in February, wearing a ball cap and a hoodie pulled tightly around his face. However, his legal status at that time was not fully known due to age restrictions on public disclosures. A judge on Feb. 6 mandated that T.H. must wear an electronic tether while living with an uncle, a ruling later amended to allow temporary work with his father at a landscaping business. Experts believe this case falls under federal jurisdiction due to the death occurring in international waters.}