Thieves stole a shark called Helen from an aquarium by disguising it as a baby and smuggling it out in a pushchair.
The grey horn shark, less than 2ft long, was snatched from the San Antonio Aquarium in Texas and put into a bright orange pickup truck used as a getaway vehicle, video showed.
Surveillance footage captured two men and a woman casually removing the fish from a petting tank on Saturday afternoon.
The dripping shark appeared then to have been wrapped in a blanket.
A member of aquarium staff challenged the group but was unable to stop them leaving, according to local reports.
“The suspects staked out the pool for more than an hour” before making their move, the aquarium said in a statement.
Police have now said the shark, known to aquarium staff as Miss Helen, has been returned alive – and one person has confessed to the theft.
Investigators in the San Antonio suburb of Leon Valley said the person was arrested and charged on Monday night.
Local news station KSAT12, an ABC affiliate, reported the arrested person was a 38-year-old man. Television viewers phoned in with tips about the distinctive van when the footage was broadcast, the station said.
Police chief Joseph Salvaggio says two others are expected to be charged. No names have been released.
Mr Salvaggio added that the truck used in the heist was recovered on Monday evening.