Her terrified security detail whisked her to an emergency hideout after a hitman allegedly located her secret hideaway and stuck a death warrant to her door.
The chilling message read: "I know where you are, I'm coming to put a bullet through your brain."
According to National Enquirer it "set off a complete panic" and the security team had to assume that Casey's head would be blown off the moment she stepped outside the house.
A source close to the team revealed: "There are plenty of people who want to kill Casey because they believe she got away with murdering little Caylee.
"Her bodyguards rushed her off in the middle of the night to another safe house a prearranged safe hideout that was available in the event of such an emergency."
They added that decoy vehicles were also used so the 'killer' would not know which one Casey was in, as they took every precaution to prevent her being identified.
Because of the terms of her probation for cheque fraud, Casey must stay in Florida for one year and report every month to a probation officer.
But she has repeatedly moved around the state moving to a rural location near Gainsville and a condo in New Smyrna Beach.
It's not the first time Casey, who has been dubbed America's most-hated mom, has been threatened - her lawyers have received hundreds of sickening messages.
But this is closest anyone has come to getting near her.
The source added: "It just shows how vigilant we will have to be. People will take a long time to forget about her."