Glad you posted. The fear has a rational base, even one w/out PTSD could feel fear and worry.... It's been a few days since your post - how are you doing?

I was looking around the web - it seems like a great question, what does someone do when a sex offender moves into the neighborhood - what is in place to keep everyone safe, monitor the situation, etc? This can't be only the concern of a few people

Quite a few sites outlines how the state or area handles paroling these offenders back into the community, the safety measures in place....it might give you some peace of mind to find out how your area handles this, what are your options as a neighbor, etc.

One site: Tip Sheet: Concerned About Sex Offenders In Your Neighborhood | Stop It Now lays out some concrete steps and plans

The San Diego site give a good reference as to how a county, etc spells out the parameters, what a community can do....Sex Offenders, Sex Offender Monitoring and the Law - San Diego County District Attorney

Perhaps contacting the local p.d. could give you some answers, outline your rights, provide some advice how to stay safe...?

I have PTSD, as well - for me, having more information helps me feel more in control about things I'm afraid of....

Take care; hope you will post again....