Associated Press - February 4, 2010 3:04 PM ET

CHICAGO (AP) - Gov. Pat Quinn saw one problem vanish today but is facing a new predicament.

Quinn's opponent in Illinois' Democratic primary - Comptroller Dan Hynes - formally conceded. But now Quinn has to deal with the revelation that his voter-selected running mate was once arrested for domestic battery.

Quinn says he knew nothing about the abuse allegations against Scott Lee Cohen until after Tuesday's vote. That's when Cohen won the lieutenant governor nomination and they were paired up on the Democratic ticket.

Quinn says Cohen needs to fully answer all questions about the charges, and the governor predicts Cohen ultimately will have to drop out of the race.

Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.