One of two former judges accused of taking kickbacks to send youths to for-profit detention facilities has agreed to plead guilty to a federal racketeering charge. Michael Conahan, a former Luzerne County judge, will plead guilty in the $2.8 million “kids for cash” scandal, according to an agreement filed Thursday in Scranton. Prosecutors said Mr. Conahan and another former judge, Mark Ciavarella Jr., took kickbacks from the owner and builder of two private juvenile detention facilities.