The stepmother of a Florida cheerleader who died mysteriously on a cruise ship has filed an emergency motion to postpone a hearing in a proceeding with her ex-husband, claiming she cannot testify because it could be incriminating to herself or one of their minor children in the criminal investigation into her stepdaughter's death.In an emergency motion filed in Brevard County, Shauntel Kepner, formerly Shauntel Hudson, asked the judge to postpone a December hearing due to the FBI investigation into the death of Anna Kepner, who was found dead on a Carnival cruise ship on Nov. 7."The Respondent has been advised through discussions with FBI investigators and her attorneys, that a criminal case may be initiated against one of the minor children of this instant action," Shauntel's lawyer, Millicent Athanason, wrote to a Brevard County judge.NO CAUSE OF DEATH FOR CHEERLEADER FOUND DEAD ON CRUISE SHIP AS REPORT REVEALS REMAINS FOUND HIDDEN UNDER BEDA law enforcement source told Fox News Digital Wednesday that authorities have recovered surveillance video from the cruise ship showing Kepner with a "suspect" and that the FBI is reviewing hours of additional footage from the cruise before her death.In an emergency motion for temporary relief filed Monday, Shauntel's ex-husband, Thomas Hudson, revealed that the couple's oldest child, 18, had moved in with him after an alleged "violent altercation" between himself, Shauntel, and her new husband, Christopher Kepner, who is the late cheerleader's father.Read the father's emergency motion:Further, Hudson's filing alleges their second son, a 16-year-old, "is now a suspect in the death of the stepchild during the cruise.""The [16-year-old]'s future has been put in jeopardy because of the choices made by [Shauntel]," according to Hudson's filing.The teen's current whereabouts are unclear. According to the filing, he has been released from custody and is staying with an unnamed third party.FBI INVESTIGATES CARNIVAL CRUISE SHIP DEATH IN MARITIME MYSTERY THAT CAN BE ‘VERY COMPLEX,’ FORMER AGENT SAYSHudson is accusing his ex-wife of alienating him from their two youngest children and arguing that his lack of involvement in their life is negatively impacting them.In a separate response, Shauntel's lawyer denied that their eldest child had been involved in a violent altercation and denied that she refused to allow Hudson time-sharing under the terms of their custody plan.Neither Shauntel nor Athanason responded to requests for comment. In the motion, the lawyer noted that her client has a right against self-incrimination, and she argued that testifying in the divorce proceeding could "be prejudicial to her or her adolescent child" in the criminal investigation."An extremely sensitive and severe circumstance has arisen wherein the Respondent/Mother will not be able to testify at the hearing at this time," Athanason wrote."Currently, there is an investigation being conducted by the [FBI] arising out of the sudden death of [18-year-old] Anna Kepner," the filing continues. "Ms. Anna Kepner, the deceased, is the daughter of the Respondent's paramour and the Respondent and the minor children of this instant action were all on the cruise ship together."The filing is part of a dispute stemming from Shauntel's divorce from her ex-husband, Thomas Hudson.Authorities have said little about the case.The FBI's Miami office is investigating the matter. And the medical examiner's office in Miami-Dade County is handling the autopsy, although no cause and manner of death have been determined as of Wednesday morning.The Daily Mail reported Tuesday, citing two unnamed sources, that Kepner's remains had been discovered wrapped in a blanket and covered in life jackets under the bed in her cabin on the Carnival Horizon cruise ship.Carnival said in a statement it is cooperating with the FBI. The FBI did not respond to a request for comment.