Teenager’s death on Carnival cruise ship ruled a homicide as how she died also revealed

The death of an American teenager found dead on a cruise ship earlier this month has been ruled a homicide.

Anna Kepner, 18, died on the Carnival Horizon cruise ship November 7 while she was on holiday with her family.

She was reportedly found dead under a bed, wrapped in a blanket and covered by life vests.

Know the news with the 7NEWS app: Download today Arrow

Details of Anna’s death had been scarce and the Miami Dade Medical Examiner’s Office had declined to provide a cause.

However according to a death certificate obtained by US news network ABC, it’s now been revealed Anna had been suffocated.

The certificate said the teenager “was mechanically asphyxiated by other person(s)” and the date of injury was listed as November 6.

Her family had previously said the FBI thought Anna had suffocated from a bar hold — when someone puts their arm across a person’s neck.

Anna’s 16-year-old step-brother is now being treated as a suspect in her death according to a legal document in a separate case.

No charges have been laid.

Anna had been on the cruise ship with her grandparents, father and two siblings as well as her father’s new wife and that woman’s children from a previous marriage.

Anna Kepner, 18. Credit: NBC

Barbara Kepner, Anna’s grandmother, told ABC the teenager and the suspect “were just like brother and sister” and were “two peas in a pod”.

“I know that those two kids cared about each other in the right way,” Barbara said.

“I can’t accuse him because I don’t know what happened in that room.”

Barbara said Anna and her step-brother had been staying in a room together along with another teenage sibling.

“The two younger girls stayed with the parents and then the three teenagers, they decided amongst themselves they wanted to stay in the room together,” she said.

“But we had a larger room and we made it very clear that at any time if they weren’t getting along, they didn’t want to be together, we had an extra bed in our room that they could come to.”

The 18-year-old was holidaying on the Carnival Horizon cruise ship when she died. Credit: Carnival

Anna’s ex-boyfriend Joshua Tew told Inside Edition she was afraid of her step-brother.

He alleged the step-brother was sexually harassing Anna and said he once saw him trying to climb into bed with her.

Anna’s younger brother, who was also staying in the same room as her on the cruise ship, told Tew he heard the step-brother yelling at Anna and telling her to shut up.

“That’s when (he) knew something was going on,” Tew said.

“Something was like banging around and stuff. Like the chairs were getting thrown around the room.”

Anna’s family has been told preliminary information indicated no signs of sexual assault.

There also did not appear to be drugs or alcohol in her system.

Barbara said the step-brother was an “emotional mess” during questioning.

“He couldn’t even speak. He couldn’t believe what had happened,” she said.

After the cruise ship docked in Miami he was taken to hospital for psychiatric observation but released to stay with a family member.

The FBI is continuing to investigate.