The death of Florida cheerleader Anna Kepner – whose body was found under a bed in her cruise ship room – was formally ruled a homicide, according to a report.

Kepner, 18, “was mechanically asphyxiated by other person(s)” on Nov. 6 while aboard the Carnival Horizon with her family, according to her death certificate issued Monday and obtained by ABC News.

Confirmation that Kepner was killed comes as federal authorities have reportedly been looking into her 16-year-old stepbrother as a “suspect” in the case that has captured national attention.

It was also revealed last week that Kepner was allegedly strangled in a bar hold.

A formal autopsy and toxicology report have not been released yet.

Kepner was on the voyage with her grandparents, father, stepmother, siblings and stepsiblings when she was slain.

Her body was found under a bed, stuffed in a blanket that was covered by life vests on Nov. 7.

Kepner’s 16-year-old stepbrother was named an FBI suspect in court documents.

Her 14-year-old younger brother reported overhearing “yelling” and “chairs being thrown” while Kepner and her stepbrother were alone in their stateroom, which the three siblings shared during the cruise.

He unknowingly slept feet away from Kepner’s concealed corpse the same night she was killed.

The family realized Kepner was missing the following morning, and her body was later found by one of the staff members who was cleaning their room.

Joshua Westin, Kepner’s ex-boyfriend, claimed she confessed she “didn’t feel safe around” her stepbrother months before her death.

Westin also accused the stepbrother of sexually harassing and having a creepy obsession with Kepner, but said she stayed quiet “because she was scared that he would do something to her.”

Westin’s father also alleged that the stepbrother “always carried around a big knife.”

“He’s like infatuated, attracted to her like crazy. He always wanted to date her,” he said.

Kepner, a devout Christian who was just baptized in May, was set to graduate from the Temple Christian School in Titusville, Florida this school year.

From there, she aspired to join the US Navy and eventually become a K9 police officer.

Her heartbroken family described her as a “beauty” who “lived every day with her whole heart” in her obituary.

“She had a big, beautiful heart, often sending random ‘I love you’ messages or little gestures that made someone’s day,” they wrote.

The cheerleader’s biological mother found out about her daughter’s death via news reports.

Kepner’s grieving mother lambasted her ex-husband for not even “try[ing] to contact [her]” to let her know their daughter had died.

She claimed she was even banned from attending Kepner’s memorial service as her ex-husband threatened to have her arrested if she “[stepped] foot in Florida.”