The FBI has opened a criminal investigation into a sexual battery that allegedly happened aboard a cruise ship that sailed from New Orleans to the Caribbean last month.

The incident happened March 24 aboard the Carnival Triumph, when a 48-year-old woman was reported missing to ship security, according to court records.

The woman had last been seen inside a nightclub aboard the ship but was later found inside the cabin of a Georgia couple, who were staying on the eighth floor of the ship.

The woman later complained of feeling sick and said she had been missing her underwear. She also said during a medical exam that the couple "had touched her places you should not be touched," according to the FBI.

Agents searched the couple's belongings and found "blue powder in a clear zip-lock bag" and various pills and capsules, according to court filings. 

No charges have been filed in the case. The FBI is handling the investigation because the incident occurred over international waters, in the Gulf of Mexico.