I just watched the press conference with the Las Vegas Sheriff. He said, "Did this person get radicalized unbeknownst to us and we want to identify that source." ISIS is doubling down in taking credit.
UPDATE: It was picked up by Infowars and linked by Drudge this morning.They have the clip.
UPDATE #2: ISIS has released a video claiming the attack as revenge for attacks on them. View it at the Daily Mail.