As I said, someone else will have to research and find the quotes, I don't have WT literature any more. It could have been in the KM, the WT, it could have been in letter form (BOE letters) but I doubt that. It wasn't just some local elder's opinion, it was "from Bethel" as they used to say. At least one of the mentions came with the requisite scary story, something about unscrupulous prisoners knowing that putting on the pretense of reform might lessen their prison time, another one came with the warning that prisoners would feign love for a sister who, in her innocence, would fall in love with the prisoner, leading to all sorts of complications because it was all fake.
If you have a good memory for dates, the first mention that I can remember was around the time the Lloyd Barry - Japanese Prisoner who became a brother story was circulating on cassette tape.
Somebody else will have to take it from here, that's all I remember.