A long-serving Illinois state senator from Lake County is resigning after being charged last month with federal tax evasion.

Democratic State Sen. Terry Link, of Vernon Hills, tendered his resignation late Friday, offering no public explanation for leaving a post he has held since 1997.

Link’s departure comes as he’s facing deepening legal troubles, and he was expected to be arraigned in federal court Wednesday.

Before federal investigators in Chicago last month charged him, Link’s name surfaced in the federal bribery case against former state Rep. Luis Arroyo, D-Chicago, who was accused last fall of offering to bribe an unidentified state senator with $2,500 to help advance legislation legalizing sweepstakes gambling in Illinois. The bribe offer was captured on a government recording.

Arroyo pleaded not guilty.

WBEZ has confirmed that senator was Link, though the 73-year-old senator adamantly insisted to WBEZ that he was not a government mole.

Senate President Don Harmon, D-Oak Park, issued a short statement late Friday acknowledging Link’s departure but sidestepped any reference to the criminal case against him.

“I look forward to welcoming and working with a new senator from Lake County,” Harmon said. “We’ve got a lot of work to do for the people of Illinois.”

WBEZ reporter Tony Arnold contributed.

Dave McKinney covers Illinois state politics and government for WBEZ. Follow him on Twitter @davemckinney.