Five people were killed in the crash of a Mexican military medical aircraft in Galveston Bay, according to officials, which was flying in thick fog.
There were eight people on board the small Beechcraft Super King Air 350 twin turboprop plane, which was carrying a child who needed burn care at a hospital.
The director of Galveston's airport said such planes from Mexico arrive several times a year in the area, often bringing patients to be treated at Galveston hospitals.
The plane flew out of Mexico earlier in the day and arrived in the area during a time of very low visibility.
The plane went down Monday afternoon along the portion of the Galveston Causeway that links to Galveston Island. In total, five people were killed, with one still missing and presumed dead. Two people, a nurse and a companion, survived the crash.
The Texas Department of Public Safety is leading the investigation into details, including the cause of the crash.