A gun-buying spree: 33, mostly rifles, in the last year. A gambling binge: more than $100,000 in recent months and, reportedly, eight hours the night before the attack. An Airbnb room: rented in September overlooking an even larger music event for an unknown reason. Investigators are wondering whether something changed in the gunman’s life around October 2016, and whether he acted alone. As President Trump and the first lady visited victims and first responders in Las Vegas, agents interviewed the gunman’s girlfriend in L.A. “He never said anything to me, or took any action I was aware of, that I ever understood to be a warning that something horrible like this was going to happen,” she said, according to a statement read by her attorney.