Among the attendees at the festival was former President Obama's daughter, Malia. That festival featured Chicago's Chance The Rapper, who also performed at Lollapalooza on August 5.
Paddock booked two rooms at the Blackstone Hotel in Chicago, located right across the street from Grant Park where the festival takes place, according to TMZ.
Though rooms with a view of the park can't be guaranteed, Paddock berated the hotel manager and was able to secure rooms that overlooked the park.
Thursday, TMZ broke the story - which was later confirmed by the Chicago Sun-Times - that Paddock booked the rooms for early August, coinciding with Lollapalooza.
So far, examinations of Paddock's politics, finances, any possible radicalization and his social behavior - typical investigative avenues that have helped uncover the motive in past shootings - have turned up little.
They are slowly piecing together his movements in the days before he caused panic and carnage at what was supposed to be a nice night out.
The unity service on Friday came after dozens of people, many wearing shirts that said "Vegas Strong", marched from Mandalay Bay to City Hall.
McMahill also said that authorities don't have any information that anyone else used Paddock's room key.
"If you know something, say something", said Aaron Rouse, agent in charge of the Las Vegas FBI office.
On October 2, Paddock opened fire from the 32nd floor of the Mandalay Bay Hotel. The official wasn't authorized to discuss the matter publicly and spoke to The Associated Press on condition of anonymity.
Paddock opened fire on a music festival in Vegas on Sunday night, killing nearly 60 people and wounding hundreds more. He killed himself as police were preparing to enter his room. Investigators haven't determined whether Paddock was considering targeting the festival, Lombardo said.
Paddock's girlfriend, Marilou Danley, 62, said in a statement that she had no idea what he was planning or why.
Newton added that forcing entry into the room with an explosive before finding Mr Paddock's body and an arsenal of weapons was like something "out of a movie".
"There's all kinds of things that surprise us in each one of these events".