Las Vegas gunman may have scoped out other music festivals

This photo combination shows some of the victims of the mass shooting that occurred at a country music festival in Las Vegas on Sunday, Oct. 1, 2017. Top row from left are: Heather Warino Alvarado, Steven Berger, Denise Burditus, Sandy Casey, Andrea Castilla, Denise Cohen, Austin Davis and Tom Day Jr. Second row from left are: Stacee Etcheber, Brian Fraser, Keri Lynn Galvan, Dana Gardner, Angie Gomez, Rocio Guillen, Charleston Hartfield and Nicol Kimura. Third row from left are: Jessica Klymchuk, Rhonda LeRocque, Kelsey Meadows, Calla Medig, Sonny Melton, Adrian Murfitt, Rachael Parker and John Phippen. Bottom row from left are: Melissa Ramirez, Jordyn Rivera, Quinton Robbins, Bailey Schweitzer, Laura Shipp and Brennan Stewart. (AP Photo)
This photo combination shows some of the victims of the mass shooting that occurred at a country music festival in Las Vegas on Sunday, Oct. 1, 2017. Top row from left are: Heather Warino Alvarado, Steven Berger, Denise Burditus, Sandy Casey, Andrea Castilla, Denise Cohen, Austin Davis and Tom Day Jr. Second row from left are: Stacee Etcheber, Brian Fraser, Keri Lynn Galvan, Dana Gardner, Angie Gomez, Rocio Guillen, Charleston Hartfield and Nicol Kimura. Third row from left are: Jessica Klymchuk, Rhonda LeRocque, Kelsey Meadows, Calla Medig, Sonny Melton, Adrian Murfitt, Rachael Parker and John Phippen. Bottom row from left are: Melissa Ramirez, Jordyn Rivera, Quinton Robbins, Bailey Schweitzer, Laura Shipp and Brennan Stewart. (AP Photo)

LAS VEGAS (AP) - Investigators are looking into whether gunman Stephen Paddock scoped out bigger music festivals in Las Vegas and Chicago - and perhaps Boston's Fenway Park - before setting up his perch in a casino hotel and raining fire on country music fans.

Paddock booked rooms overlooking the Lollapalooza festival in Chicago in August and the Life Is Beautiful show near the Vegas Strip in late September, according to authorities reconstructing his movements.

It was not clear if he contemplated massacres at those sites.

The details came to light as investigators struggled to figure out why Paddock opened fire on a crowd of 22,000 Sunday night from the 32nd floor of the Mandalay Bay hotel casino in Las Vegas. He killed 58 people and injured nearly 500 before taking his own life.

A federal official said authorities are looking into the possibility Paddock planned 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.

Authorities previously disclosed Paddock had 1,600 rounds of ammunition in his car, along with fertilizer that can be used to make explosives and 50 pounds of Tannerite, a substance used in explosive rifle targets.

Investigators have been combing through his background but remain stumped as to his motive.

The profile developed so far is of a "disturbed and dangerous" man who acquired an arsenal over decades, Sheriff Joseph Lombardo said. However, investigators have been frustrated to find he lived a "secret life," Lombardo said, "much of which will never be fully understood."

The weekend before the massacre, Paddock rented a room through Airbnb at the 21-story Ogden condominiums in downtown Las Vegas and stayed there during a music festival that included Chance the Rapper, Muse, Lorde and Blink-182.

In early August, Paddock booked a room at Chicago's 21-story Blackstone Hotel that overlooked the park where the Lollapalooza alternative music festival was being held, though there's no evidence he actually stayed there, a law enforcement official said Thursday.

Although Paddock killed himself as a SWAT team closed in, the sheriff said it appeared he had planned to survive and had an escape plan. Lombardo would not elaborate on the plan.