The video was taken on June 26, but it didn’t go viral until a month later, when it was posted on Instagram by Mark Quartiano, who leads shark-fishing expeditions and is known as Mark the Shark.

He said he received the video on July 24 from the men who recorded it via direct message on Instagram. Mr. Quartiano shared the video via his own Instagram account that day. That post has been viewed more than 73,000 times.

“I couldn’t believe that someone would send me something like this,” he told The New York Times in July. “I was horrified.”

Multiple people sent complaints to the commission.

According to a criminal affidavit, Mr. Wenzel, Mr. Heintz and Mr. Benac recorded several videos — and also took photographs — during their expedition that revealed numerous criminal violations.

Prosecutors say that Mr. Benac initially shot a blacknose shark with a spear gun — which is illegal to do — while fishing near Egmont Key in Hillsborough County, Fla. The men then recorded themselves dancing on the bow of the boat, officials said.