"Watch yourselves out there guys. I don't want to be part of some kind of sick prisoner ring."
Sounds more like someone being an asshole by posting this. Disgruntled monger who didn't get what he wanted, or more likely an ex-boyfriend out to settle a score.
Think about it. If it was really a "do-gooder" saying these things, they would have called the police themselves, even from a payphone, instead of posting a bunch of personal information on Craigslist. This was a personal attack. Fortunately, this post was flagged out of existence, and rightly so.