ST. PAUL, Minn. — A St. Paul man has been charged with enticing teen-age girls to send sexually explicit photos and videos online and then demanding more – and more. It was sexploitation, prosecutors said. Yue Vang, 31, was charged in federal court. There were more than 500 victims, prosecutors said. The criminal complaint alleges that Vang posed as a female online. After his targets sent lewd images, he threatened to distribute the pictures and videos to each victim’s family and friends if they didn’t send more. This went on five years, prosecutors said. Conviction could mean a mandatory minimum sentence of 15 years in prison.