LAS VEGAS—The gunman who murdered at least 59 people at a country-music concert on Sunday might have originally targeted another Las Vegas music festival held the previous weekend, according to a senior law enforcement source.

Stephen Paddock rented multiple condos overlooking the annual Life Is Beautiful Festival, which this year was headlined by Lorde and Chance the Rapper, said the source, who is not directly involved in the investigation but has been briefed on its progress.

In an effort to confirm the report, The Daily Beast visited the Ogden, a 21-story luxury condominium tower with a line of sight to the concert-grounds.

“We're not in a position to confirm or deny anything about Mr. Paddock's dealings. I suggest you contact Metro [police]. As you know this is an on going investigation,” said Melissa Warren, public affairs officer for Fais Foley Warren, owner of the Ogden.

The source suggested that Paddock may have lost his nerve or simply changed his plans and checked into the Mandalay Bay Hotel on September 28. He then took a suite overlooking the Route 91 Harvest Festival and opened fire on an estimated 20,000 concertgoers below. Law enforcement recovered 23 weapons from the suite, including several rifles capable of automatic fire. Paddock concealed the arsenal in 10 suitcases, Joseph Lombardo, the sheriff of the Las Vegas Metropolitan Police Department told reporters.

Law enforcement discovered at least 19 firearms, thousands of rounds of ammunition, and an explosive at his home in Mesquite, Nevada. The bomb-making chemical ammonium nitrate was also found in his car, police said.