I wish I had the answer...sometimes I'm the same way. My mind gets zeroed in on something and I just can't stop. In college, I happened across the schools offender registry, turns out my lab partner was convicted of CSA....I completely freaked out. After that, every class I enrolled in, I checked the registry against the student list and dropped classes with offenders. I do that for my neighborhood too.

The only thing I can suggest is talking about it in therapy, my T is helping me understand the difference between keeping myself/my family safe and compulsively looking for danger around every corner.