Can't say for sure whether they will, but if you sent as much evidence as it sounds like you did, I hope they do!
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Based on my experience I believe they will - or at least your letter (if it properly identifies the person(s) involved) will end up in his file at the time of his naturalization interview and may be a topic of discussion.
If a lawyer was involved the investigation will include (and maybe will focus) on him or her. That's "red meat" for ICE or CIS - as it should be.
That is entirely up to the government.
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