Salinas police are seeing a rise of cases involving online predators targeting minors. Officials say the number of cases has increased to 15 a month. Predators contact victims through social media websites and apps including Facebook, Snapchat or Instagram, and ask for nude photos. The predators then use the pictures to extort the victims and demand more photos. Several arrests have been made so far. Police are urging parents to monitor their teenagers’ social media accounts.