Coworker is creating an uncomfortable, sexualized work environment for others. What are my responsibilities, and what should I do?

Question

Short version

I work in an academic lab in North America. One of the senior members of the lab has a pattern of inappropriate sexualized behavior and sexualized bullying with young women at work (this might be sexual harassment, I'm not sure). Part of his job is to mentor and train students and lab techs, often women. We have similar positions but he's worked in the lab longer than me and is close with our boss. What are my professional responsibilities, and how can I stop his behavior?

Long version

I first heard about his behaviour when a student told me he makes her feel uncomfortable. Things like standing too close to her, comments on her clothing, and sexual jokes. About a year after that he said some misogynistic things over drinks. I later invited him to a party and he immediately put his arms around my female friends, talked down to them, and otherwise acted like an ass. They told me afterward how uncomfortable he made them feel. I stopped inviting him out, but otherwise I didn't do anything and we remain friendly at work.

However things escalated last night when I talked to a female coworker over drinks. She told me that she's leaving the lab because of harassment from him (partly sexual, partly personal conflict, I don't know the full story but they do not like each other). She also told me that many students have had similar problems with him, and that multiple women have left the lab feeling very uncomfortable about his behavior. Again things like standing too close, inappropriate touching, sexual comments, belittling comments, misogynistic comments. Other stories came up of just angry, creepy, misogynistic behavior. I now realize it's about half the women in the lab that he's done this to.

The woman who's leaving said she tried to resolve this with our boss. Our boss's solution was to have a group meeting with the two where he took the harasser's side. He then told her to "talk it out" with the harasser. Our boss and the harasser are good friends. This is why she's leaving.

I now think his behavior is a problem at work. I want to do something. Here's what I think I need to do:

• Talk to people in the lab and warn them, tell them they can report it, come to me for support, etc.
• Warn people coming into the lab about his behavior.

I don't think that's enough though, because it doesn't hold him accountable and because it doesn't actually stop the bad behavior. So here's what I think I could do:

• Talk to our boss and tell him how bad it is.
• Talk to the guy doing this and tell him to stop.
• Contact someone in the university administration (not sure who). Our university is very proactive about sexual harassment.

One caveat is that our boss can pick favorites and this guy is definitely one of them. They're friends. So I can imagine repercussions. That said, I've been enabling this guy and I am so sick of that. What should I do to make sure this stops?

I don't know if his behavior constitutes formal sexual harassment. Also, while I've heard about behavior that I would consider harassment I've only seen a few things personally, and those are bad (IMO) but not harassment (misogynistic comments over drinks, creeping out friends at a party). What I know to be true is that he has a pattern of making women feel uncomfortable and someone is quitting her job because of it.

Answer 1

Short answer: Take the complaints outside your boss's sphere of influence with as much evidence as you can gather.

First thing to ask is, when talking to your boss, are you explicitly using the term "sexual harassment"? This is a term that has a very specific meaning to your HR department and will in almost all cases be taken very seriously. If you boss is ignoring this, then this does not bode well for him.

Next, you need to make very sure that each of the victims record everything that happens. Times, dates, places, what was said, who said it. This needs to be very detailed. The more evidence you have from more victims and witnesses, the greater chance of this sticking.

Finally, take this either to your institution's HR department or to student services. For students, they should absolutely go to student services with their evidence.

Ensure that your boss's behaviour is noted in the documentation about his friendship with the perpetrator and his solution telling you to work it out. This is utterly unacceptable as it places the resolution into the hands of the person with the power.

This MUST go outside of your boss's ability to hide it, but the more evidence you have, the more chance you have of getting a result.

Remember though, this is not going to be an easy path. It will get nasty, and it will be difficult for you personally if you are coming in as advocate. But evidence is the key here. The more victims that come forward, the more chance you have of having this situation resolved and the person(s) abusing their authority being dealt with appropriately.

Also, while having you as an advocate is very important, it really has to be the victims who take their evidence forward to HR or student services. While your being there carries a lot of weight, nothing will carry more than the testimonials of those directly affected by the harassment.

Answer 2

• You need to get your female colleagues and the students that are being harassed to notify the universities' authorities about their experiences.
  
• You personally can only speak about your own observations, anything else is mere hearsay.
• You must not warn people coming into the lab about his behaviour!
  That is defamation of character and will land you in trouble.

There is a legal framework set by law and company / university policies and if indeed he broke such laws or policies there will be consequences.

Also, make sure not to conflate sexual harassment or attack with other, less serious misbehaviour.
"Acting like an ass" for instance (as despicable and character describing it may be) is not nearly as serious in this context.

Another thing:
In the setting of a party it isn't automatically sexual harassment to have physical contact (i.e.arm around shoulder - I'm not talking about "grabbing them by their secondary sex organ").
That is how people bond, communicate their interest and affection, often awkwardly begin courting, hook up, even find life partners.
Women for instance often touch you when they talk.
It is natural behavior and usually nothing sexual, though it can be flirtatious and affectionate.

Physical contact becomes harassment if a person made their displeasure about it known and it continues to happen against their will !
Mind you it is more problematic in cases of boss / subordinate, teacher/student etc. - where there is a difference in authority or power.

Edit:
The answer from Jane S. popped up after I sent mine and she raises many valid points and indeed detailed documentations are very important.
I'd also like to emphasise that I don't think, you should be a "lone wolf" in this fight!
You certainly could be a driving and empowering force behind your colleagues and the students that fell victim to harassment and you may inform your superiors and the dean about this but ultimately you will need the victims speaking out in order to have a success in changing the situation.

Please explain the downvotes!
My answer is sound advice in accordance with lawful and social behaviour.
Not to mention largely overlapping with another answer getting upvotes.
I "might" have an idea why but I'd like to see the reasons spelled out ... (;