Jeff Martin - Associated Press

Anna Kepner's cause of death on a Carnival Horizon ship was “mechanical asphyxia," according to a copy of her death certificate obtained by ABC News. The nature of a floating crime scene can make investigations challenging.

The man in his 30s was found unresponsive after riding the coaster at Epic Universe on Wednesday. He was taken to a hospital, where he was pronounced dead.

A sheriff’s office internal affairs investigation found that the airman “did not make any hostile, attacking movements, and therefore, the former deputy’s use of deadly force was not objectively reasonable.”

The attacks off beaches in the Florida Panhandle led authorities to temporarily close several beaches to swimmers on Friday. Beaches were reopened Saturday, with flags warning of high hazards.