MARATHON, Fla. – A 63-year-old Jacksonville man was arrested Friday after threatening a Florida Keys mayor, deputies said.

Michael Falls is accused of leaving multiple threatening messages directed at Marathon Mayor John Bartus.

An investigation began when Bartus told the Monroe County Sheriff's Office he received six voicemails earlier this month from a man identifying himself as Falls.

"The profanity-laced messages suggested Mayor Bartus was responsible for Falls' interaction with law enforcement" or that Bartus "controlled law enforcement in some fashion," sheriff's spokesman Adam Linhardt said.

Falls left several threatening messages, Linhardt said, including one in which he told Bartus, "When I'm done, I'm going to show you your grave, sir."

The rambling messages also contained odd statements and allegations, such as Falls' belief that law enforcement officers are out to get him and that they put bees and spiders in his truck, while demanding that Bartus provide him with a list of names of all those people trying to "shut him down."

Falls claimed in one voicemail that he has the "highest FBI security clearance" and that if someone follows him into a room and he says shoot, "they will shoot you," Linhardt said.

In another message, Linhardt said, Falls told Bartus to "run the sheriff out of this (expletive) town. Am I making myself clear? It's called a smart bomb. 6 a.m."

"We take these sort of cases very seriously and I want to thank our middle Keys deputies and detectives for making a quick arrest in this matter," Sheriff Rick Ramsay said. "We will continue to work to protect our elected officials who in turn strive to help us make our communities as safe as they can be."

Detectives said Falls left similar messages at City Hall.

Falls was arrested on charges of aggravated stalking and threats against a law enforcement officer or elected official.

Linhardt said Falls admitted to leaving the threatening messages.