Multiple investigations are ongoing; this is one of them.
I predict multiple things happening.
First of all, the MCSO's made a habit of setting up fall guys. An attorney got fired over that flap a few years back where they had the publishers of the New Times arrested, and of course there's that lengthy complaint from a few weeks ago trying to pin everything on Chief Deputy Hendershott. (Arpaio hands it off to his buddy Pinal Sheriff Babeu, in the hopes that it'll go away, but if Babeu DOES go off-script, Hendershott gets in trouble and Arpaio -- hypothetically, at least -- gets away clean.) Expect to see more of the same with Aubuchon, though I don't think Arpaio will turn on Thomas unless he's absolutely desperate. He'll stick to the "this is a witch hunt" story. (It is, of course, a witch hunt; it's just that Thomas was the guy conducting it and that's why he's looking at disbarment.)
I think what's going to be interesting is seeing which cronies circle the wagons and which turn on Joe. If Bill Montgomery isn't a complete moron, he's going to take this as an object lesson in what happens to county attorneys who use their office to harass and intimidate the Sheriff's political enemies; I expect he'll be a lot more reluctant to serve as Arpaio's attack dog than Thomas was.
And I see Babeu supporting Arpaio as long as it's politically convenient and then turning on him as soon as THAT'S politically convenient. He's got the most to gain here: he can be the NEW America's Toughest Sheriff.
So, in summary: no, nothing sticking to Arpaio just yet, but the entire department's getting investigated at the county, state, and federal level and his cronies are starting to go down. It's only a matter of time. It took a very long time to finally get this far, but now it's all happening pretty quickly.