Anna Kepner, an 18-year-old high school senior and cheerleader, was found dead on a Carnival cruise ship during a family vacation in November.

A nna Kepner, a teenager who was found dead on a Carnival Horizon cruise ship this month, died by asphyxiation resulting from a bar hold -- an arm across the neck -- a source briefed on the investigation told ABC News on Friday. Investigators also found two bruises on the side of her neck, the source said.