. >> reporter: yeah, john and kari, we are here near encanto park where earlier there were thousands of kids, not so much right now, just a couple of trick or treats, zombies outside the park. all of the children were out having tonight, and u.s. around, looking at high risk sex offenders making sure they are complying with all of the rules. thousands of valley kids around the valley trick or treating, showing off costumes and cashing in on their candy. >> let's see your costume, show the camera. >> queen of hearts. >> reporter: and what's your favorite thing about trick or treating? >> to get free candy. >> get candy. are having fun, the u.s. marshal's service is making sure they stay safe, all a part of safe treat. six teams of probation officers and u.s. marshals are going around the valley, knocking on the doors of high risk sex offenders. >> we are making sure they are compliant and doing what they are supposed to do. u.s. marshals service says sex offenders have strict guidelines when it comes to halloween activities. >> individuals that are on probation have been told that the