Scuttlebutt was that Scalia was killed to open up a spot for Loretta Lynch. Part of the deal to make Hillary's legal problems wrt classified materials go away. That was the topic at the Sky Harbor tarmac meeting, according to the rumor.
Rumor was bolstered by Lynch saying a short time later that she'd go by what FBI recommended, whereupon Comey was trotted out with his, "No prosecutor would take the case", speech. And the fix, as they say, was in.