An 18-year-old Central Florida student was found dead aboard a Carnival cruise ship earlier this month while vacationing with her family.
The family of Anna Kepner, a soon-to-be high-school graduate, is speaking publicly for the first time about her mysterious death and the loss they are grappling with.
Authorities have released few details. But a death certificate provided to ABC News by her family states that Miss Kepner died of "mechanical asphyxia", with the date of injury listed as 6 November.
Ms Kepner was on vacation in the Caribbean with her father, stepmother and three step-siblings when she was discovered dead in her cabin.
Here's what we know about the case.
Anna Kepner's body was found under a bed, wrapped in a blanket and covered by life vests, ABC News reported.
The death certificate provided to the network by Anna Kepner's family states that she "was mechanically asphyxiated by other person(s)".
The Miami Dade Medical Examiners office did not confirm ABC's reporting and declined to provide any more information to the BBC, citing an "active and ongoing investigation".
The FBI has not named any suspects, and no charges have been filed.
Much of what is publicly known about the family's trip comes from an interview Miss Kepner's grandparents gave to ABC news.
The family was travelling on the Carnival Horizon, a family vacation that included Miss Kepner's father, one of her biological siblings, a brother, her stepmother, and her stepmother's children from a previous relationship. Her grandparents were also on board.
"We were all having a great time," said her grandmother Barbara Kepner. "I couldn't fathom why anyone would wanna hurt my baby."
Her grandparents said she was expected to graduate from high school in May and planned to join the US Navy.
"We were looking forward to seeing her grow," her grandfather Jeffrey Kepner said. "The cruise itself wasn't what made me excited. It was the fact that I was gonna get to spend another week with my youngest son and his family and all the grandkids."
The Kepners said that the relationship between Anna Kepner and her step-siblings was a happy one, adding there was "no such thing as steps".
"It's all family. It's a blended family, yes, but that's not how our family is," Jeffrey Kepner said. "Our dynamic is we're all just family."
Barbara Kepner recalled that the last day she saw her granddaughter alive, the teenager had complained about her braces bothering her.
Despite the discomfort, she dressed up and joined the family in the cruise casino, her grandmother said.
Barbara Kepner said her granddaughter told her "Meemaw, I love you guys, I'll see you later."
"And we never saw her again after that," she said.
Her grandparents are now desperate for answers.
"I now know how she died," Barbara Kepner said. "It helps a little bit, but it's not going to bring Anna back."
The cruise company told the BBC it is fully cooperating with the FBI's investigation.