okay. Obviously there's been some kind of miscommunication. The responses to this thread have been largely ridiculous.
To clarify:
My original request was for proper legal channels for them to go through to end this investigation.
The reason I ask is because they worked hard for this house (nice place. kinda pricy.) and in the course of this investigation they interviewed their neighbors. A few of those neighbors have sent them letters and one lady even knocked on the door asking them to move out.
I would also never suggest to my friends that they submit a false affidavit. The ex roommate is a drug dealer. That was the reason he was asked to leave. He didn't grow or manufacture but he procured and disseminated. I think anyone that sells meth to children (srsly 13 and 14 year olds) should probably be in jail. That's just my opinion though. And because of that, I went ahead and called the cops and gave them his info myself. So if there's any repercussions it will be on me and I'm more than capable of taking care of myself. His idea of being a "badass" is a large rusty machete replica with a completely flat blade edge.
Also, any time you plan on dealing with law enforcement and the judicial system, you want a lawyer or some kind of legal advocate present. Even if you are completely innocent. A few of my family members are lawyers and although I've avoided jail the 27 years I've been alive without calling in any favors, I've learned that a lot of cops just want the confession.
Thank you to those that offered actual advice on how to proceed with this situation. They, nor myself, have ever been involved in something like that and I assumed, based on the context, some people would have some information regarding the best way to proceed.
To those who threw a tantrum and spouted pejoratives for no apparent reason: While I understand this is the internet, and flaming is something to be expected, this is a grown up discussion. Why don't you go play some xbox or, even better, get hooked on phonics?
and before it comes back to bite me in the ass, I know what I said earlier. I did tell them it's a terrible idea to lie to the cops. We had a good laugh about the whole situation and I instead took care of that part myself without revealing my identity and without lying.