Updated

The man accused of stealing a horn shark from a Texas aquarium Saturday by disguising the fish as a baby may have posed as a salt supplier about a month ago to stake out the exhibit and prepare for the heist, staff members said.

Three suspects were arrested after a gray horn shark was taken from the San Antonio Aquarium’s tide pool exhibit around 2:15 p.m. Saturday. Surveillance video showed the trio "staked out the pool for more than an hour" before stealing the sea creature with a net. They then placed the shark, dubbed Miss Helen, in a bucket and onto a baby stroller before whisking it out of the building.

Anthony Shannon

Anthony Shannon, 38, is accused of stealing a gray horn shark from the San Antonio Aquarium on Saturday. (BCSO)

The strange heist caught the aquarium by surprise, but staff members believe planning for it may have begun a month ago.

Aquarium spokesperson Jamie Shank told KENS5 she believes one of the suspects paid a visit to the aquarium a month ago, but disguised himself as a salt supplier. The man asked to test the exhibit’s water quality — possibly a way to examine which animal he could steal.

Anthony Shannon, 38, was named the mastermind of the shark heist after he confessed to the crime, officials said. He was charged with felony theft.

Though staff members did not specifically name Shannon as the person who posed as the supplier, Leon Valley Police Chief Joe Salvaggio said the alleged shark stealer had been planning the heist for weeks.

Photos and videos from Shannon’s house showed “almost a mock-up” of an aquarium, KENS5 reported.

"The garage, in particular, there was, what is being described as a 6,000-gallon salt water tub that didn't even have a top. It was a huge tub and a 2,000-gallon one that was basically, floor to ceiling with all types of different marine animals," Salvaggio said.

"There's no way the shark would have survived. It still doesn't make sense that it did survive but they were prepared inside the house and probably in the vehicle to transport this thing," Salvaggio added.

Shannon reportedly has a rap sheet that dates back to 1998, when he was arrested for marijuana possession, KSAT reported. He was indicted in May 2002 for aggravated assault.

The police chief said Miss Helen has returned to the aquarium for visitors to see “for the years to come.”