Las Vegas mass murderer Stephen Paddock researched famed Fenway Park in Boston and the location of the latest Lollapalooza music festival in Chicago, NBC News reports.
Former President Barack Obama's daughter Malia attended one of the Lollapalooza shows at Grant Park, which was held Aug. 3-6.
The reports raise the possibility that Paddock was contemplating attacks at those sites.
Fenway Park, in addition to being the home of the Boston Red Sox, has hosted several concerts in recent months, including Lady Gaga and Billy Joel.
"We are aware of the media reports and are in contact with our local and federal law enforcement partners here and in Las Vegas," Boston Police said in a statement Thursday.
Paddock booked a room at Chicago's 21-story Blackstone Hotel that overlooks Grant Park, but didn't show up, and there's no indication he actually traveled to either Boston or Chicago, NBC reported.
Also, the weekend before the massacre in Las Vegas, Paddock rented via Airbnb — and checked into — a condo in a 21-story luxury building in Las Vegas that overlooked the Life is Beautiful alternative music festival, Sheriff Joseph Lombardo said Tuesday.
That music festival featured Chance the Rapper, Muse, Lorde and Blink-182.
The Associated Press contributed to this report.