Madman Stephen Paddock researched attack locations in Chicago and Boston before settling on Sin City, according to reports published Thursday.
The 64-year-old retired accountant went as far as booking two hotel rooms in the Windy City that overlooked the Lollapalooza music festival held in early August.
The rooms Paddock secured at the Blackstone Hotel offered a clear view of the outdoor festival, according to the Chicago Tribune.
His reservation extended across all four days of the event — which drew hundreds of thousands of people, including former President Obama’s daughters Malia and Sasha.
Paddock also researched hotels near Fenway Park, the home of the Boston Red Sox, a senior law enforcement official told NBC News.
The lodging near Fenway offers, at best, an obstructed view of the ballpark — and Paddock ultimately gave up on the search, officials said.
He also looked up another potential target in Beantown, the Boston Center for the Arts, officials said.
It wasn’t established whether Paddock ever ventured to either city, officials said.
The revelations of Paddock’s interest in other potential targets emerged as investigators struggled to dig up clues into the motivations behind the deadliest shooting in modern American history.
An armed-to-the-teeth Paddock built a sniper’s nest on the 32nd floor of the Mandalay Bay Resort and Casino before unloading on revelers enjoying a country music festival.
A total of 58 people were killed and 489 others injured in the Sunday night massacre. Paddock shot himself in the head as cops closed in.
A new report said Paddock also fired bullets at jet fuel tanks located about 1,100 feet from the Route 91 country music festival.
One bullet penetrated a tank but did not cause a fire or explosion, the Las Vegas Review-Journal reported.
“Airport fueling has not been compromised,” McCarran International Airport spokesman Chris Jones said. “It’s functional.”
Investigators were looking into the possibility that Paddock planned additional attacks, including a car bombing, a federal law enforcement officials said.
Paddock filled his car with 1,600 rounds of ammunition, along with fertilizer that could be used to make explosives. His vehicle also contained 50 pounds of Tannerite, a substance used in explosive rifle targets.
The Blackstone Hotel released a statement Thursday saying it’s cooperating with authorities.
“We can confirm that there was no guest under that name who stayed at our hotel in August during the Lollapalooza music festival,” it read. “We can confirm that a reservation was made under the name Stephen Paddock, however authorities have not confirmed that this is the same person as the Las Vegas shooter.”
Boston police commissioner William Evans said the city was preparing to beef up security at upcoming Red Sox games and other public events.
“We are going to step up, we are going to step up our attention,” he said, according to the Boston Globe.
A week before the attack, Paddock rented a room overlooking the three-day Life is Beautiful festival in downtown Las Vegas.
He used Airbnb to book the room at the 21-story Ogden hotel.
The concert, which ran from Sept. 22 to 24, featured Chance the Rapper, Lorde and Blink 182.
With News Wire Services