Transcript for Bishop Richard Malone defends his decision to return accused priest to ministry
Reporter: Matt golden isn't father Dennis's only accusers. There was others. One of my friends, Nick, he was also an altar boy and molested by father Ryder. Reporter: His best friend Nick is now dead, but he told he'd been abused. Reporter: There's a letter written to your predecessor, back in 1992. I'm aware of that one. Reporter: Report being impropriety that he says he witnessed. There may be as many as three victims, and yet, father Ryder is still in active ministry. He is. Reporter: Why? Because, again, that whole case went to our review board. And you have to know that these members of the review board are all very respected members of the community. All with expertise, you know, in childhood sex trauma, all legal things and the salient facts in the allegation didn't line up. Typical church posturing. Reporter: This attorney represented many of the sex abuse victims in the Boston spotlight series. Actor Stanley Tucci played him in the movie. If he hadn't smeared the cardinal's good name we wouldn't even be here. I object to the word smear. Reporter: He now has nearly 40 clients in Buffalo, including the boy described in the seminarian's letter. He doesn't think much of the church's investigation of father Ryder. It's meant to enhance the image of the church and defend Dennis Ryder. Reporter: The investigator told us he turned his report over to church lawyers and outlined the findings to the board. One day later, bishop Malone reinstated father Ryder. Did you speak with this seminarian? No, it's not part of my role to do that. Reporter: Did you speak with any of the victims? This, the victims of this case never came to me. I see victims, I'm seeing a victim this week. Whenever victims wish to meet with me I meet with them. I think's a joke. I could sit square and look into this camera today and say I'm still waiting for your phone call, bishop, and I have not heard a phone call, an e-mail, nothing from him personally. To me. Or to my friend's family. Reporter: "Nightline" obtained a copy of the investigator's report in which he concluded that the 1992 letter written by the seminarian was a fabrication. He also said there were too many inconsistencies in the story. We showed the report to ABC's sunny Hostin, a former sex crimes investigator herself. It is clear to me that either the person who wrote the report didn't have significant experience in investigating child sex crimes or did not come to this conclusion in an unbiassed way. Reporter: The investigator accepted father Riter's denial, despite his admission he had failed to polygraph test. He took a lie detector test. He took a lie detector test and failed, and yet it was okay to go ahead and put him back in the ministry. Baffling to me that he still has a job in the diocese. Reporter: "Nightline" reached out to father Riter. His lawyer told us these are not new matters. They were fully investigate the and found to be wholly lacking in merit. He says dredging up these long-discounted allegations on this late date serves only once more to harm father Riter's fair reputation as a faithful servant of god. Bishop Malone stands by his decision to put him back in the ministry, including giving children first communion. Do you think the parents would be comfortable if they knew all the facts? I don't know. I'm comfortable because I know a thorough investigation was done by a competent professional. Reporter: No one can second guess his decision. Apart from the Vatican, no one closely supervises how individual bishops handle these cases. They are a law unto themselves. Who do bishops obey? Bishops obey our conscience. We try to do that. We obey the central teachings of scripture and tradition. Ultimately, we are, we obey the pope. Reporter: Has anyone at the Vatican contacted you with concerns? Reporter: Wanting more information? No. Reporter: Not at all? Not at all. Reporter: Adopted this summer by the U.S. Catholic leadership could bring greater accountability for bishops when there's an allegation of abuse or covering up. But Shavon o'connor feels a lot more could be done. Reporter: Do you think bishop Malone should go to jail? That's a hard question for me. Because he wasn't alone. Reporter: Would you be testifying against him? I would. Yes. So, in that regard, my testimony might, might result in him going to jail. And, again, it's hard, because I do know him personally, sadly. I think he does need to go to jail. But I would visit him. Reporter: We played that exchange for bishop Malone. Sadly, I think he does need to go to jail. Wow. But I would visit him. That is a shocker to me. And disappointing and very distressing. That's all I can say. Reporter: You understand the depth of her anger and disappointment? Not entirely. Not entirely. To say she thinks I should go to jail, I find, I'm almost speechless, speechless to hear that. Reporter: The bishop says he has no plans to resign and no one, at least not in Buffalo, can force him. Meanwhile, the FBI is currently investigating the diocese.
This transcript has been automatically generated and may not be 100% accurate.