@Anonymous----The aunt is still alive, my bio mother is not
If your father's been in prison for 35 years, that would mean you're an adult. You could write to him and tell him you'd like to see him, and that you would like to meet at a public restaurant to have lunch. Don't expect too much, because he's been out of society for so long, he will be socially awkward, he won't have much money at all (you will probably have to pay for lunch) and he will be embarrassed and probably depressed. He may act somewhat angry at society, but that has nothing to do with you. If he agrees to have lunch, tell him you're happy that he's out and in the free world. Don't belabor the point. Don't offer him money, and don't let him beg for money or manipulate you in any way. Keep the meeting brief and don't make any promises. Tell him you're most appreciative to his sister for raising you. That should be about it.
You did not say if she were alive, so you can ask her opinion. Do think that it is the fact that his own sister raised you, can be a form of mercy towards him, just to help in any way, and see where it goes from there. Don't raise your hopes about anything, but don't shut out any doors either, since if he were to die, you need to have a right psyche that you tired and he rejected, or you tried and he tried, and you are both at peace, due to the fact, that you have a long life ahead of you and would have kids to raise and you have your conscience clear, because you cannot choose your dad. Hope it works out for you both.
Perhaps tell your aunt you would be interested in meeting him if he wanted to meet you too. As she knows him since childhood, she would probably be able to speak to him about your wishes and judge his reaction. If his response seems favourable, your aunt could help organise a meeting and be there to introduce you and help you both be comfortable with the initial meeting, and generally help things go smoothly at the start.
I'd be very careful about that. Keep your distance. I understand he's your father but he's also a hardened criminal. 35 years in prison is not something to overlook. Don't be used