I don't think that any attorney, who participates in this forum, will advise you on how to "set a trap" for someone (in court or elsewhere).
You can present evidence in court, but the rules of evidence are complex. Another aspect of civil litigation is the "no suprises" process of discovery, also complex. None of this promises any success without an attorney. Give up the idea of vengeance and define for your attorney your real objectives, which should be the best interests of your son.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.
You need to consult with a local family law attorney to see what options, if any, you have. It is not advisable to persist on your own with this vendetta, as it will surely backfire on you.
Attorney Inga Stevens is licensed in Maine. She provides general information on Avvo.com. No attorney-client relationship arises out of the information given here.