A criminal investigation has been launched into Jeffrey Epstein’s cushy 2008 jail stay in Florida — where he allegedly abused young girls while under a supervised “work release” program.

Palm Beach County Sheriff Ric Bradshaw announced the probe in a statement on Thursday night, saying “an active criminal investigation” had been opened in addition to the internal affairs probe that had been launched by his office last Friday.

Democratic state Sen. Lauren Book had urged Gov. Ron DeSantis to authorize an investigation in a letter Monday, which reportedly prompted countless threats from people telling her to back off.

The lawmaker pointed out how Epstein was allegedly allowed to leave his Palm Beach County Jail cell nearly every day of his 13-month sentence under a “work release” program. Lawyers for the financier’s accusers claim he instead spent his time at a private office — where he had “improper sexual contact” with women.

Epstein, who pleaded guilty in 2008 to prostitution-related charges involving underage girls in Florida, is currently facing up to 45 years in prison for the alleged sexual abuse of minors, some as young as 14.

He had been sentenced to 13 months behind bars in the Sunshine State and was allowed to leave on work release 12 hours a day, six days a week.

Florida state law currently bans sex offenders from being freed on work release, but there does not appear to have been any such rule in place back in 2008.

With Post wires