[Not A Snowbird]

I don't have my books handy, so I will have to check it out a little later.

I never leave home without them:

"From what I found out after he died, he got in so far, then panicked abut what he was being asked to do and tried to back out. Well, you just don't hand in your resignation to Voldemort."

Here's a thought... was Regulus asked to do the same thing Draco was asked to do? Hmmmm?

[retrokitten]

Could be.

Going on the assumption that he was the RAB from the note he would have to have knowledge of where the horcruxes were hidden and how to retrieve them or be a very powerful wizard.