A 16-year-old from Florida charged with sexually assaulting and killing stepsister on a cruise ship

Court records show his defense lawyers did not object. An email and voicemail seeking comment from Hudson'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.

“Our hearts go out to the victim’s family during this unimaginable loss,” U.S. Attorney Jason Reding Quiñones said in a written statement. “A federal grand jury has returned an indictment charging serious offenses that allegedly occurred aboard a vessel in international waters."

Kepner was a high school cheerleader at Temple Christian School in Titusville, Florida, some 40 miles (65 kilometers) 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 extremely rare. Hudson was seen at the Miami courthouse in February, wearing a ball cap and a hoodie pulled tightly around his face. But his status at that time was not fully known because his age barred public disclosures by his lawyers, the government or the court.

A judge on Feb. 6 said Hudson must wear an electronic tether while living with an uncle. The order was changed to allow him to join his father for a few days last week at a landscaping business, court records show.

Experts believe the case is in federal court, and not a state court where teens are commonly prosecuted, because Kepner died in international waters.