STRATFORD - Stratford police warned Internet users today after they say a local man admitted to extorting numerous women using Facebook. Authorities say Jon Lisi used Facebook messages to demand nude photos from a total of six women. They say he knew the victims and that he was finally tracked down after a months-long investigation. Detectives say computer-based crimes are on the rise, with about 75 percent of their caseload pertaining to the Internet. Police say there may be more victims. Anyone with information is urged to contact them at 203-385-4100.