Forty-five men face arrest for allegedly having sex on public beaches in Florida, authorities said.

Martin County Sheriff William Snyder told WPTV that deputies already arrested 21 men, including a registered sex offender, for allegedly performing sex acts at Martin County’s Bob Graham Beach and Joe’s River Park.

The arrests were part of “Operation Mangrove,” a two-month investigation tasked with identifying people having sex in public areas where families and children are present.

Snyder expects to make 24 additional arrests by the end of the week.

“We have very clear, very graphic video evidence,” Snyder told the station. “There is nothing left to the imagination.”

Authorities caught all the men suspected of the lewd acts on hidden cameras over the course of the investigation. Investigators launched “Operation Mangrove” after several people called detectives with reports of naked men having sex along the beach’s boardwalk.

“I think that this is a subculture of people who have their own methodologies for meeting each other,” Snyder said. “They seem to have their own verbal, non-verbal cues that let them know that they’re both there for the same reason.”

Police then identified the suspects from their license plates before they made the arrests.

Snyder said authorities will continue the investigation at other undisclosed locations in Martin County.

“My first concern when I learned about this behavior was for the safety of families,” Snyder said. “Right after one or two of these sexual encounters, a family – uninvolved in any behavior – happened to just walk right by.”

Police have busted others for engaging in sexual activity on public beaches this summer.

In July, authorities busted four teens for allegedly having sex at a Cape Cod beach on Fourth of July weekend.

Authorities arrested a British couple for allegedly having sex in the ocean at a Thailand beach later in the month.