Minnesota Sen. Justin Eichorn resigned from the state Senate on Thursday in the wake of a federal criminal charge accusing him of soliciting sex from someone he thought was 17, but turned out to be an undercover cop.

Republican state Sen. Justin Eichorn resigned on Thursday following his arrest earlier this week in an underage prostitution sting. Eichorn submitted his letter of resignation, effective Thursday, less than an hour before the Minnesota Senate was set to take an unprecedented vote to expel him from the chamber.

Former Minnesota Sen. Justin Eichorn resigns and appears in federal court after being arrested in an undercover sting operation.