A man named Stephen Paddock reserved a room at the Blackstone Hotel, in Chicago, at the same time as the Lollapalooza music festival was taking pace in the IL city.
Both rooms had a checkout date of August 6, corresponding with the final day of the music festival that drew tens of thousands of concert-goers to Grant Park alongside Lake Michigan.
Officials say the Las Vegas shooter rented a room in downtown around the same time as an alternative music festival held September 22-24.
According to TMZ, Paddock had never booked a hotel room and never showed up for his reservations.
"We are aware of the media reports", the statement said. 59 people have been confirmed dead, and another 500 were injured in the attack.
The revelations raised the chilling prospect that Paddock had been planning an attack for at least two months before he launched Sunday's assault on a country music festival in Las Vegas, raining bullets on the crowd from a nearby hotel tower.
They also know he rented an apartment in a Las Vegas high-rise over another music festival the weekend before the massacre, though not why.
Paddock booked the rooms through a third party - Expedia.
Paddock bought the.308-caliber and.223-caliber tracer ammunition from a private buyer he met at a Phoenix gun show, a law enforcement official not authorized to comment on the investigation said on condition of anonymity.
Wynn said Paddock didn't run up debts or have a gambling problem, and he had "the most vanilla profile one could possibly imagine".
Even the No. 2 official in the Federal Bureau of Investigation said Wednesday he was surprised investigators have not uncovered more about why a man with no obvious criminal record would cause so much bloodshed.
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.
FBI Deputy Director Andrew McCabe said he was surprised Paddock had provided so few clues, and that has proved challenging.
While we don't know if Paddock ever checked into any of the rooms, it's clear that things could have been disastrous if he had chose to attack people at the event.