Parents, Police Monitoring Kids' Cell Phones  (CNN) --Mike Harris was watching his local TV news when a segment caught his attention: Parents were using software to monitor their kids' cell phones. Harris, an investigator for the Child Sex Internet Investigations Unit in Jefferson County, Colorado, thought the service could be a new tool for combating sexual predators. Equipping his phone with the software, Harris posed as an underage child on social-networking sites and began luring pedophiles. He immediately got results. Since then he has made 83 arrests of alleged sexual predators -- 44 of them with the help of the monitoring program. "It makes it easy for me as an investigator. It saves hours of time and I have more time to go out and catch offenders". The software also documents text messages and other data that can be used in court, he said. "Now all I have to do is go into the account and pull everything out that was done between that sex offender and me." Programs such as My Mobile Watchdog and Mobile Spy are becoming increasingly popular with parents as more school-age children are carrying cell phones. Parents say the services help them protect their kids against predators and also reduce "sexting," the growing practice of using mobile phones to share sexually explicit text messages and pictures. In 2008, Jessica Logan, a Cincinnati, Ohio, teen, hanged herself after her nude photo, meant for her boyfriend, was sent to teenagers at several high schools, exposing her to ridicule and taunts. Once a child's phone is equipped with the software, the parent or law enforcement officer creates a list of contacts -close relatives, trusted friends that are authorized to communicate with the minor's phone. An online file, accessed by the parent stores activity related to the child's phone, including text messages and shared photos. Any unauthorized number that contacts the child's phone gets flagged, and the parent receives a real-time text message alerting them to the infraction. A monthly fee is about $10 for the service, which only works on so-called "smart phones" with Web access. My Mobile Watchdog also will alert parents if their child has removed the software from their phone. eAgency Mobile Solutions of Newport Beach, California, is the creator of My Mobile Watchdog. Bob Lotter the CEO, said he never imagined it would become a tool for authorities cracking down on online sexual predators. "The threat is huge," he said. "There are so many ways for child predators to find victims-- through Google, Yahoo, MySpace, Facebook and a host of other sites." A Colorado, woman said she outfitted her 12-year-old daughter's phone with monitoring software after the girl was sexually assaulted by a man she met on MocoSpace, a mobile chat network. She said it has given her more peace of mind and her daughter a greater awareness of the responsibilities of having a cell phone. Some privacy advocates might object to parents digitally eavesdropping on their kids without their children's consent. But an Asheville, North Carolina, mother, who fitted her son's phone with the software without his knowledge, disagrees. "This is my son. So to me it's not like I'm wiretapping him. Besides, privacy in my house is earned."