Namechanged as wish not to be identified.... will give full story so as not to dripfeed (have slightly changed some facts also)
I have 2 what I thought were good, longterm friends. They regularly rent out a cottage adjacent to their home to friends of theirs for months at a time. A number of months ago I visited them briefly with my DDs and got a horrific sense the current lodger took too much interest in my girls.... it was like shiver going down my spine. I have never had this sense before, chose not to mention it at the time (did mention it subsequently to a different friend in passing) but made a mental note not to let this man near my kids (he was offering to become more involved in their lives, become friends, help out etc).
It became apparent last week during a night out from another friend (who had being informed by someone who recognised this man from the media) that this guy was a convicted sex offender, who had being placed on the sex offenders register for child related offences (though the registration had since expired).
AIBU to feel the most angry 

i have ever felt in my life that these 2 friends failed to inform me of this mans background - I believe placing my DDs in potential danger? They were aware of his conviction but believed (based solely on his story) that he was incorrectly convicted and was no harm to children.
I feel like these people have played russian roulette with my DDs innocence - how would you feel.