He was indicted. That's "pressing charges". There were, as I understand it, complications with getting him extradited. Several people who post or posted here spoke with the US federal authorities fairly often, and with Canadian authorities now and then.
My own theory was that in part it was a special situation, and in part the Feds didn't want to pick up the bill to house him in jail in Vegas for years before the trial began. After all, they knew where he was.