postdocs - 1.5 years later, how to make sure unprofessional behaviour by former mentor has consequences?

I was a post doc at a large US university for a year and after took another postdoc position in my home country. My mentor was a tenure track assistant professor. It pretty soon became clear that working together was going to be difficult due to different ideas on how to approach and manage projects. Furthermore, I might eventually not have been the best fit for that position given the somewhat different topic of my PhD work. This ended in a complicated work relationship, in which several requests on my side calling for meetings to discuss ways to improve the situation were ignored.

All the while, in my opinion, I was treated abusively: in group meetings in front of the whole lab, I felt humiliated by unconstructive discussions and was called out for the too little progress I made. In smaller meetings with up to two other lab members, I was shouted at by my mentor and told I didn't deserve my PhD etc. Sometimes, reasonable questions of mine were answered in a passive-aggressive way. Furthermore, the significant amount of time I spent in helping more junior lab members in their (very ambitious) projects was not appreciated.

At the time, I asked a university official in charge of postdoc affairs for advice. I was being told that a formal complaint at HR or the department head would most likely have no direct consequences. I furthermore feared retaliation, mostly because my J1 visa and housing depended on that position. For these reasons, I did not take any further action.

At one point, I decided to quit the lab after the initial agreed-upon one-year duration of my stay. Two and a half months before I wanted to inform my mentor in a one-to-one meeting about my decision, but two e-mail requests for that meeting ("to discuss the fact that my contract ends", which is how I worded it) were ignored. I eventually managed to get hold of my mentor after a group meeting and in the following conversation, after asking me why I think the whole thing didn't work out, they did not acknowledge any wrongdoing or unprofessional behavior on their part, even after I brought up several examples.

Other, more junior lab members (PhD and master students; I was the first and only postdoc) reported similar incidents of unprofessional behavior, but also didn't speak up. My guess is that they, too, were fearing retaliation and didn't want to jeopardize the relationship with their supervisor.

My question now is how to achieve the following (in decreasing order of importance):

• have my former mentor improve their behavior so that they treat future students and employees better


• if that doesn't happen, make sure their propensity for unprofessional behavior is known to the tenure committee


• be sure the other professors in the department know that both sides are to blame for what happened; that is, restore my reputation


• find closure: I'm going to leave academia for industry soon, but feel my academic career could have been more successful and my stay in the great city this lab is located in even greater had it not been for the terrible time at work (although this might possibly be hard to answer and / or worth of its own question)

While I am aware that there are several questions on this site about similar issues, I believe mine is different because I left that lab a year and a half ago. I fear that, after such a long time, simply contacting the department chair will come across as bitter and and as wanting to retaliate at the end of my academic career.

edit:

As per Dan Romik's suggestion: I'm not only interested in advice how to achieve the above goals, but also whether this is actually adviseable. Also, as the time span of 1.5 years indicates, this isn't a super urgent matter for me. But I've been thinking about this question for a long time and I really appreciate all of you answers, most of them taking very different point of views! I don't know which one to accept - a natural choice would be to follow the suggestions I find most promising and see how it works out. Although not being accepted, this wouldn't make the other answers less valuable.