Passengers on the ship told said they woke up to the sound of sirens at around 3 or 4 a.m. Wednesday, and one heard a request for medical assistance on one of its decks, according to KHOU.

The FBI is investigating the death of a Texas man on the Carnival Dream cruise ship, with no trauma signs evident.

Euvelester Villarreal Jr., 48, died aboard the Carnival Dream ship in the early morning hours last Wednesday, officials with the Galveston County Medical Examiner’s Office confirmed to MySA on Tuesday. Villarreal was a resident of Rio Grande City, the county seat and largest city in rural Starr County in the Rio Grande Valley.