There is no prohibition against an attorney taking these types of cases on a contingency fee basis; however, you would need to find such an attorney. I have taught at a seminar where another attorney spoke. He is an excellent attorney but said that he never takes a contested probate on a contingency fee basis unless he believes his contingency fee is going to be substantial. There is a lot of work involved. Good luck.
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I can't speak to the merits of the case without reviewing the file, but I can tell you that most attorneys don't handle cases like this on a contingency basis unless (a) they believe you have a solid claim and (b) an inventory has been filed to show some indication of the value of the case. When it comes to probate matters, contingency cases are the exception, not the rule (at least in my experience).
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I agree with my colleagues. You have a lot of red flags and serious concerns. However, the biggest challenge you face is that you need a great deal of evidence to prove your case. This is going to require a very good attorney, as well, because you cannot do this on your own. I would gather all of the evidence that you have and at least meet with an attorney to discuss this in more detail. The attorney should be able to give you a much better idea of the strengths and weaknesses of your case and whether or not it is worth pursuing.
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