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MIAMI (CBSMiami) – He may be smiling in his mug shot but a South Florida man is facing a serious charge after reportedly threatening to kill state Rep. Jose Felix Diaz on Facebook.

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Steve St. Felix, 24, allegedly made the threat on Sunday against the legislator. The post said St. Felix would kill the lawmaker if he appeared at a political meeting.

Miami-Dade police said St. Felix posted on Diaz’s Facebook page, among other things, “I’ll kill your (expletive) if you show up at the next Republican Executive Committee meeting.”

“I saw that somebody had tagged me and they had explicitly threatened me more than once, saying they wanted to kill me,” Diaz told CBS4 News. “Obviously, I’m a family man, and I have two younger kids, and a wife and it was a spooky thing to see.”

St. Felix reportedly admitted to making the threatening post after his arrest and that he is “fed up with the Republican Party.” Investigators also said St. Felix said he meant no actual harm and that he had failed to take unspecified medication at the time.

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“He had a history of mental illness and a criminal record, so it was a perfect recipe for us to be concerned,” Diaz said.

The lawmaker and his family were under constant police guard from Sunday until St. Felix was nabbed Monday night.

Very much on the Republican legislator’s mind was the attack on Republican members of Congress earlier this month, that left House Majority Whip Steve Scalise critically wounded.

“I’m obviously vigilant and constantly careful with how I act in public and the way I comport myself,” Diaz said. “A threat Mike this is something you can’t take lightly these days.”

St. Felix is jailed on a charge of making written threats to kill or do bodily injury.

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His bond was set at $500,000.