A 16-year-old boy charged as an adult in the death of his 18-year-old stepsister on a Carnival cruise ship has pleaded not guilty in federal court.
The teenager, identified in court documents by his initials, was accused by federal prosecutors of sexually assaulting and intentionally killing Anna Kepner aboard Carnival Horizon while the ship was in international waters in November 2025.
Prosecutors said the case was first handled as a juvenile matter before a federal grand jury indicted him as an adult on charges of first-degree murder and aggravated sexual abuse, according to ABC News.
Investigators said Kepner was found dead on the ship during a family cruise, and the Miami-Dade Medical Examiner later ruled the cause of death mechanical asphyxiation. Prosecutors said the alleged assault and killing happened while the vessel was traveling toward Miami, and the case fell under federal jurisdiction because it occurred in international waters, Justice reported.
Read more: Former FBI Agent Warns Key Fact in Anna Kepner Cruise Ship Murder Case Will 'Complicate Matters'
The arraignment was scheduled for Wednesday in Miami, but the defendant waived his appearance, and the not guilty plea was entered through court filings. The adult prosecution followed a sealed juvenile case and a court decision to transfer the matter to adult status.
The defendant faces first-degree murder and aggravated sexual abuse charges, with a maximum penalty of life in prison if convicted. Prosecutors said he is presumed innocent unless proven guilty, and the FBI continues to investigate the case.
Anna Kepner's father, Chris Kepner, is married to the suspect's mother, Shauntel Kepner. Chris and Shauntel Kepner said their family is devastated by Anna's death and continues to grieve the loss.
Family members have publicly called for accountability and said they hope the case will bring justice for Kepner. The stepbrother has not yet been taken into custody, and no court date has been set as of Monday afternoon, as per NBC News.
