LAS VEGAS — Authorities reconstructing the movements of Stephen Paddock before he opened fire from his hotel room sniper's perch said Thursday they were looking into whether he checked out larger music festivals in Las Vegas and Chicago.
He booked rooms with views of the Lollapalooza festival in Chicago in August and the Life Is Beautiful show near the Vegas Strip in late September, officials said.
More about the deadliest mass shooting in modern U.S. history:
A U.S. official said authorities are looking into the possibility that Paddock was planning additional attacks, including a car bombing.
The official wasn't authorized to discuss the matter publicly and spoke to the Associated Press on condition of anonymity.
Paddock booked rooms overlooking the Lollapalooza festival in Chicago in August and the Life Is Beautiful show near the Vegas Strip in late September before he undertook the deadliest mass shooting in modern U.S. history, according to authorities.
Investigators looking into Paddock also came across mention of Fenway Park, Boston police Lt. Detective Mike McCarthy said, though he provided no further details.
An executive casino host described Stephen Paddock as an analytical gambler who would try to identify video poker machines most likely to provide big payoffs.
Host John Weinreich at the Atlantis Casino Resort and Spa in Reno, Nev., said Paddock would sit for hours, placing bets of $100 or more, rarely interacting with anyone but always conscious of his surroundings and who was winning.
He also said Paddock had a "god complex" and expected quick service no matter how busy employees were.
Weinreich says Paddock liked "everybody to think that he was the guy. He didn't boast about anything he had or anything. It was just his demeanor. It was like, 'I'm here. Don't cross me. Don't look at me too long.' "
Marilou Danley, Paddock's girlfriend, returned to the United States from the Philippines on Tuesday and was interviewed Wednesday by FBI agents in Los Angeles.
The 62-year-old said in a statement read by her lawyer that Paddock had sent her to see family in her native Philippines weeks earlier, and she was still overseas at the time of the attack.
She said he wired her money so she could buy a house for her family, and she was initially pleased but later feared it was a way to break up with her.
The pair met at a casino while she was a high-limit hostess for Club Paradise at the Atlantis Casino Resort Spa in Reno, his brother Eric Paddock told the Washington Post.
Danley's sisters in Australia said in a TV interview that she was a "good person" who would have stopped Paddock if she had been there and if she had known about the plot.
Nevada gambling regulators said they were sorting through documents for clues about him and Danley.
The 58 people slain in the attack included a father of six, a man who died in his boyfriend's arms and a university student who was studying health care management.
Nearly 500 others were injured. About 150 are still hospitalized, with about 50 in critical condition Wednesday night, hospital officials said.
The injured ended up in 13 hospitals scattered across southern Nevada, with most of them treated and released. One of them, Braden Matejka of British Columbia, left the hospital Wednesday for a 22-hour road trip home with his girlfriend and parents. He told the Associated Press he couldn't fly back to Canada because he had been shot in the head.
Paddock's rampage could have been deadlier without the quick thinking and tactical skills of officers who took charge, treated the wounded and directed paramedics to the most urgent victims.
Without their expertise, more people could have died, said Dr. Douglas Fraser, vice chief of trauma at University Medical Center of Southern Nevada, where many of the wounded were treated.
"It was very helpful to have people who were off-duty or medically trained there," said Fraser, noting that a victim with a major injury to an artery can die in minutes.