Anna Kepner, age 18.

By Joe Lombardi From Daily Voice

The death of a high school cheerleader found under a bed on a Carnival cruise ship has officially been ruled a homicide.

ABC News reported on Monday, Nov. 24, that the death certificate for 18-year-old Anna Kepner of Florida states she “was mechanically asphyxiated by other person(s).” The date of injury was listed as Thursday, Nov. 6, though the exact time remains unknown.

Kepner, a straight-A student and cheerleader, died by asphyxiation caused by an arm across her neck, according to a source briefed on the investigation who spoke with ABC News. Two bruises were found on the side of her neck, the source said.

Her body was discovered on Friday, Nov. 7, wrapped in a blanket and covered by life vests, hidden under a bed in a cabin on the Carnival Horizon. Security sources said the ship returned to Miami as scheduled the next day.

The FBI is leading the investigation, which is standard protocol for deaths occurring in international waters. Authorities have released few details about what led up to Kepner’s death and have not announced any charges.

Court documents from an unrelated family matter revealed that Kepner’s 16-year-old stepbrother is now considered a suspect, according to WPLG-TV, Local 10 in Florida.

The stepmother, who was also on board the cruise, requested a delay in a custody hearing, stating in court filings, “a criminal case may be initiated against one of the kids,” and “the 16-year-old child is now a suspect in the death of the stepchild during the cruise,” WPLG reported.

The stepbrother has since been released from custody and is reportedly staying with a third party, WPLG said.

According to a new report in People, family members said that the boy was "an emotional mess" when Anna's body was found.

Check back to Daily Voice for updates.