After Day on 'Most Wanted' List, Ex-USC Prof Busted Walter Lee Williams tracked down in Mexico By Rob Quinn, Newser Staff Posted Jun 19, 2013 3:33 AM CDT Updated Jun 19, 2013 4:10 AM CDT 4 comments Comments This 2011 image provided by the FBI shows Walter Lee Williams, 64. (AP Photo/FBI) (Newser) – Former University of Southern California professor Walter Lee Williams has been arrested in Mexico just a day after he was added to the FBI's 10 Most Wanted fugitives list. The 64-year-old, who is wanted on charges of sexual exploitation of children and traveling abroad for the purpose of engaging in sexual acts with children, was arrested in the resort city of Playa del Carmen, and had apparently been residing in Mexico for some time, the AP reports. Williams, who is believed to have sexually exploited at least 10 minors in countries including the Philippines, "preys on the most vulnerable children," an FBI special agent says. Click for more on Williams, a former Fulbright Award winner.