I am a first-year Ph.D. student. In the last year of my undergrad I began a research project with my then-advisor, who planned to hand me off to his former postdoc (let's call him John) who is tenured at my current institution. I believe that John is the only researcher working in this subfield at my current institution. However, I have recently learned John was actually on administrative leave for the spring and fall semesters of 2020, because he was accused of having an inappropriate sexual relationship with a female graduate student. He is back now and I do not know if the university's investigation found him at fault. I am trying to determine the appropriate path forward for myself. Currently I am tempted to quickly finish this project, with the help of my undergraduate advisor rather than John as much as possible, and then get out of that subfield; after all, I'm just a first-year, and should be able to switch without too much trouble.
I have two questions about how I may proceed. The second is more important, the first being more of an IPS.SE question than anything.
Is it appropriate to ask the department chair or another authority figure if John was found "guilty"? Though I am a man, I am uncomfortable working with John if the allegations turned out to be true. I have to weight my discomfort against the fact that I really enjoyed the project, and would strongly prefer to finish it this year. On the other hand, he's back, and teaching calculus no less, so maybe the truth turned out to not be as severe as the allegations. In any case, my decision would be a lot easier to make with this information (in fact it seems that the department may have tried to hide the reason John was on administrative leave from the first-years, though the other graduate students all knew). However, I fear that because I have not established much of a personal connection with the authority figures here (thanks mainly due to COVID) that if I ask I will just come off as a gossip.
Will having worked with John, knowing what he was accused of, tarnish my own academic reputation? I certainly don't endorse John's actions (and, again, don't know what he was actually accused of, or whether he was found guilty) and don't intend for him to be my thesis adviser -- I just want to get this one project done, and following the suggestions of this Academia.SE post it seems like I should just go ahead with the project, but I'm not sure if the reputation hit will be worth it. So suppose that I work with John, even though I know he was credibly accused of misconduct. I write a paper, coauthored with John. I recognize that my actions may come off as callous towards the victim of the misconduct, and while I don't know her identity, I strongly suspect that her research interests are similar to mine. Should I expect my reputation to suffer?