Dear "first year"...

As I have been banished to the commentary hell that is Blogger Beta, I cannot actually comment on your ethical delimma. But if I could, this is what I would say,

Jeeze, that is not the enviable position to be in.

Part of why I had to kick out "Craig," was because I was worried I might eventually have to give a statement or give testimony against a roommate/friend. Well, that, and he was just an unbearable dickface....

As unsavory as it might be I would do the interview, cooperate, and be as honest as you can (as in honestly honest). Otherwise, worst case scenario you might wind up being charged with obstructing justice or perjury or something down the line, and that would be problematic for when you have to go through the "moral character" background check the state bar does. But you're in D.C. so I'm not sure how that works. But it can't be good, and no "friend" would ask you to take that risk for him/her.

That said, there's no need to state anything that you don't recall, and you shouldn't speculate. Perhaps your friend didn't tell you stuff, or at least no details. Be honest, but you don't need to go out of the way to opine as to what may or may not have happened if you weren't there and she didn't tell you.

That's my two cents (as in not legal advice). Good luck and I hope it works out.