Anna Kepner stepbrother pleads not guilty in cruise ship killing case

Anna Kepner’s case moved into its next hard-edged phase when her 16-year-old stepbrother pleaded not guilty in federal court to murder and aggravated sexual abuse charges. He waived an in-person appearance in Miami, a procedural step that pushes the case firmly into the federal court system and sets up a fight over what happened aboard the Carnival Horizon.

Kepner was 18 and from Titusville, Florida, when she was found dead on the cruise ship in November 2025. Federal court records say the alleged conduct took place while the vessel was in international waters en route to Miami, and the U.S. Department of Justice said the teen has been charged as an adult by a federal grand jury. That means prosecutors now have to prove, case by case, that he sexually assaulted and intentionally killed Kepner.

The not guilty plea does not resolve the core dispute in the case. It only locks in the adversarial stage, where the defense can challenge the government’s account, the way evidence was collected, and whatever forensic findings or statements prosecutors eventually plan to put before a jury. For the Justice Department, the burden is clear: connect the defendant to the death with admissible evidence and convince a jury beyond a reasonable doubt. For the defense, the next fight will likely center on what can actually be proven from a death that happened at sea, away from the usual local crime scene rules.

That cruise-ship setting is what makes the case so unusual. The ship was the Carnival Horizon, the family was traveling together as part of a blended group of eight relatives, and the FBI had already been looking at the stepbrother in connection with the death before the indictment was unsealed. Kepner’s body was later found concealed under a bed in the room she shared with two other teens, including her stepbrother, and her death was ruled a homicide with mechanical asphyxia listed as the cause. Those facts, together with the international-waters setting, leave prosecutors with a case that is now as much about jurisdiction, evidence, and chain of custody as it is about motive.

Kepner’s family had been told she was set to graduate high school in May 2026 and hoped to join the Navy. Instead, the case now moves toward the slower grind of federal motions, evidence disputes, and testimony that will determine whether the government can turn an indictment into a conviction.