Unaddressed ethical violation I know about but have no connection to: Do I report it? I've been made aware of a situation that blatantly violates the honor code at my institution (also every institution). However it does not involve my lab, and the folks in the relevant lab are not keen to address it in any official capacity.  What to do?

The Situation:


A graduate student proved to be unfit for the lab he worked in. After one year he transferred to a totally different department/school/program at our university--one that is not research intensive.
Upon leaving, my friend hounded him for the data he collected, which was part of a project she is lead on.  He provided her with an excel spreadsheet. The Day 1 observations appear normal, but the subsequent days were simply a formula that changed Day 1's values by a constant and added some variance. To be clear, he actually left the formulas (which linked to the Day 1 observations) in the cells. So, clearly it's fraudulent data.
My friend told her PI and is not using any data collected by this RA in any of her work.
However, what is problematic, IMO, is that the PI and my friend have no intentions of addressing it further. I believe they are motivated by a desire to avoid the bureaucracy and the awkwardness that comes with making such an accusation. They have also pointed out that the program he is in now is totally different and does not involve real research (but still writing up reports about observed data, I would imagine).


The Question:


This student is still at our institution and I feel that the lack of ethical integrity he demonstrated should (must) be addressed!
Am I being a self-righteous, cotton-headed ninny muggins?
If not, what course of action should I take?  
NB: I am not in any way associated with that lab or PI... it's a different department too. I am a 2nd year PhD student.


Thank you for any insight.  

Bonus Details:


This was intentional fraud. The data are behavioral observations of mice, there should be original video files, and there are for Day 1 but the subsequent files are missing. When asked several times this week it was "oh yeah yeah I'll get those to you... it's just my login isn't working since I'm switching departments..." indicating that he did not actually collect the data. He did not reply "just kidding," "my bad," or "actually I did something stupid." (Sidebar: his inability to realize how obvious he is reminds me of teaching while students not-so-covertly text... I see you!)
The specific formula was Day1Value*1.1+(RAND(-2,2))... so while he added variance it was a naive attempt at doing so... even if he hadn't left the formulas in there it would be as clear as day.
I took action... After carefully reading our honor code and the procedure for reporting misconduct I felt more compelled to act.  Ultimately, I think falsifying data is one of the  worst things you can do as a scientist. I just couldn't stop thinking about the new department he is in, the new advisors he has, and the new cohort he is apart of... all ignorant of this offense.  If I was his new advisor, I would want to know about this.  So out of respect for them and for my institution I knew I would act.  The question was how?

It turns out my university has a protocol for reporting misconduct anonymously, which is great. But rather than go that route, I actually asked the PI if we could meet. PI was taken aback because, although PI knows who I am, we are not at all working together. In our meeting I simply explained that... 

"I feel compelled to act in accordance with the honor code given that I am aware of the situation.  But once I report the incident, you will likely be the first person they contact.  So I wanted to come to you instead, out of respect, and explain how I felt regarding the situation and basically find out if you prefer to take care of it or if you prefer for me to move forward acting in my own good conscious."

PI was surprisingly kind about it, empathetic even. PI was very responsive to me explaining that I mostly felt bad for the new people this person was working with, that they were ignorant to his lack of ethical integrity--something the PI had not considered. We discussed how the PI wrote the RA a letter of rec to get into the new program, and I could see a realization on the part of the PI--specifically, that he had a responsibility to let these folks know that he no longer stands by his characterization of this student. In the end, PI assured me that we were in agreement, that taking official action through our university's research office was the appropriate next step. I apologized profusely for meddling but PI assured me I did the right thing and that I would've been equally right to have reported it as well.

So in answer to my own question, I would say that...


First, read your honor code carefully to find out what responsibility you have to report incidents you know about. (This is why S.Diaxo's answer is incorrect; not only is there something I can do about it, I am technically required to do something about it).
Figure out what your options are for reporting misconduct, it may be the case, as at my university, that you can simply report it anonymously and that they will look into it and you do not need to be involved.
If you feel compelled to report something, but you want to be respectful to the people it might involve, consider talking to those people directly (in a respectful and non confrontational manner). That worked for me, and I'm glad I don't need to be the one to report it.


Thanks everyone for your discussion.