Is this guy a child sex offender? If so he cannot go out in service at all because he will come upon homes with children in them and is NOT allowed to be around kids. He is breaker the law and could be jailed immediately. I would call the local police and turn him in.
If he is not a child sex offender but is a danger to adult women, I would go to the local paper and have them do a news story on this. You will need to show them proof of his sex offender record along with proof he is going door to door, so you may want to do a stake out, or have a friend do it for you. Stake out the kh during field service and follow his group, just snap a photo of this perve so you have proof.
I am sure the community will be thrilled with JW's to see them allowing this guy to knock on their doors.
This same thing happened to my family in the Hingham MA congregation about 7 years ago. That is why we abruptly left this hall after 10 years. A sister came to my home one day and told me that the elderly gentlemen that just moved to our hall, and that my husband and I had been speaking with several times at the meetings was a convicted child rapist. I guess his pleasure was raping little boys. At the time my son was 6 and since we had been in that hall since he was born and before that and knew everyone, we allowed him to use the restroom by himself. The sister came and warned us after she said she hung up with an elder who she pleaded with for an hour to come and tell us because our son could be in danger. He declined and told her to mind her own business.
Anyway this elder was more concerned about it getting out in the community because it would bring reproach on Jehovah then protecting the smallest most vulnerable sheep in the hall. Well, I went and warned all the other parents with young children and most of them were totally outraged by this. But this one lady actually told me that I could be accused of slander for spreading this around and that we did not know if he was repentent or not but was reinstated so we should leave it in Jehovahs hands. She was not concerned at all and was the mother of TWO boys, ages 6 and 3. I could not believe her reaction.
Another thing about this elder, he had a young son at the time too. But you see, since HE was privy to the information about this guy, his son was never in danger. What a A**hole.