The Secret Service agent arrested with his belt undone after allegedly masturbating in a Florida hotel hallway had an arsenal of weapons when cops took him into custody.

TMZ obtained the body cam footage of John Spillman‘s May arrest in Miami … and the video shows the moment his arresting officers find a large weapons cache.

Police search a bag in Spillman’s hotel room … combing through Secret Service badges, a large vest, guns, a taser, and several other weapons. 

During his arrest, Spillman was seen begging cops to pull up his pants. He’d been handcuffed with his belt unbuckled and his pants undone. One officer told him, “Bro, shut up. Be quiet.” 

Another officer asked … “Why are your pants down?”

Spillman replied … “I had too much to drink.” One cop shot back, “Yeah, no s***.”

When Spillman tried to tell cops he was with the Secret Service, they scoffed … until they realized he wasn’t BS’ing them.

As we reported … Spillman was arrested at the DoubleTree by Hilton Hotel Miami Airport & Convention Center … after he allegedly followed hotel guests from the hotel lobby to their room and started pleasuring himself in the hallway.