[timwis]

Maybe the attacker simply changed your username after gaining access, paving way for them to register a new account in that name.

[scottsousa]

That's a good thought but I don't think that's the case unfortunately. My e-mail address is not associated with any Twitter account at this time.

Twitter states they cannot find an account with my e-mail address if I try a password reset. As far as I can tell, my previous account has vanished as I mentioned in my OP.

[timwis]

After changing the username, couldn't they change the email address too?

[dsl]

When they take over your account they do a forced delete and create a new account. That way they "own" the name and it is much harder to get back.