A former San Diego County sheriff's sergeant who allegedly tried to meet up with a minor for sex pleaded not guilty Friday to felony and misdemeanor sex charges. Luis Rios, 55, is accused of soliciting sex from a person he believed was a 15-year-old boy, then trying to meet with the supposed teen in person. The investigation into Rios, who had been with the department for over 25 years, was sparked by videos posted online by citizens' group People V. Preds. Members of the group posed as minors and say Rios engaged in sexually explicit conversations with at least one supposed teenager, then attempted to meet with a minor in public. MORE: https://www.cbs8.com/article/news/local/ex-san-diego-sheriffs-sgt-pleads-not-guilty-to-alleged-meet-up-attempt-with-boy/509-b1601117-446f-4548-be93-0614f6434967