What SHOULD I do to catch a thief?

I know the more astute of you probably see the similarity between this question and the question that I posted yesterday what can I do to catch a thief? Well… this is something of the follow-up/update to that question. This time however, It is an ethical dilemma. I am in a position where I CAN catch a thief… but SHOULD I do it?
Here’s the skinny:
On the advice that was given to me in my last question, I filed a police report last night.
After I did it, my little brother (A pretty shady character in his own right) pulled me aside and told me that he thinks that he might just know the guy who did it.
Apparently some neo-nazi skinhead kid that has the same MO as what happened to me (Breaking into unlocked cars with ipods or wallets left out.) knows where our house is, and was apparently pulling jobs around our area, along with a few other kids on Friday night.
Also, he doesn’t like my brother (mostly because he is a nazi skinhead and my brother is a quasi-hippie “share the love” type and tried to hug him once.) My brother says that there is a “high probability” that he will be able to get my wallet and Ipod back, but he says that in order to do this for me he would have to pull favors from some of the other kids that were participating in the crimes on Friday (Some of which were his friends) As a result, I’ll have to promise not to talk to the cops anymore and divulge the identity of the punk that stole my stuff.

Which raises an interesting scruples question:
Do I get my Ipod and wallet back, and drop the subject, knowing that the group probably will hit other houses on other nights (but not mine), or do I go against my brother’s wishes and report the information about the crime to the police, thereby taking down the entire group and possibly getting my ipod back… but also setting my brother up to be a snitch.

I am leaning towards the first option… but I just don’t know. Is it really ok to let something like this just slide, especially now that I know that the entire block was hit?