Paddock had booked two rooms at the Blackstone Hotel in Chicago, across the street from Grant Park where Lollapalooza has been held since 2005.
On September 28, the 64-year-old high-stakes gambler and real estate investor checked into Mandalay Bay and specifically requested an upper-floor room with a view of the Route 91 Harvest music festival, according to a person who has seen hotel records turned over to investigators. The official wasn't authorized to discuss the matter publicly and spoke to The Associated Press on condition of anonymity.
CHICAGO (AP) - Police say they're increasing security for Sunday's Chicago Marathon after a gunman opened fire on an outdoor music festival in Las Vegas earlier this week, killing 59 people.
Paddock also booked a room near another Las Vegas concert a week before the shooting, police confirmed.
He made the reservation on Expedia, and learned that the hotel couldn't guarantee him a room overlooking Grant Park, where the multi-day concert takes place. That festival attracts hundreds of thousands of people to the downtown Chicago park, which is framed by tall buildings.
According to the report, Paddock was aggressive and said that he need a room with a view because he would be celebrating his anniversary with his wife, and the two met at Lollapalooza.
A federal official said authorities are looking into the possibility Paddock planned additional attacks, including a vehicle bombing.
Chicago Police Bureau of Organized Crime Chief Anthony Riccio says there will be "significantly" more undercover officers working during the marathon than in years past.
Sunday's shooting happened along the Las Vegas Strip, an area brimming with hotels and casinos located in unincorporated Clark County, just south of the Las Vegas city limits. He killed 58 and injured almost 500 before taking his own life. They also said they still have no motive for the attack.
Las Vegas Sheriff Joe Lombardo said in a news conference Wednesday evening that Paddock had previously stayed at a Las Vegas high-rise condo during a music festival the weekend before the shooting.
Australian police are assisting their US counterparts on the investigation into Las Vegas shooter's girlfriend Marilou Danley.
Paddock sent Danley on a trip to her native Philippines before the attack, and she was unaware of his plans and devastated when she learned of the carnage while overseas, she said in a statement.
The official said no evidence has been found that Paddock ever came to Chicago that weekend.
Investigators said that they are looking for the "roommate" of the shooter - Marilou Danley - and describe her as a person of interest. He had no known criminal record and nearly no close friends or social media presence.
The profile developed so far is of a "disturbed and dangerous" man who acquired an arsenal over decades, Sheriff Joseph Lombardo said.