A second music festival, in which Kiwi music sensation Lorde was a headline act, is now at the centre of investigations into the motive and movements of Las Vegas massacre gunman Stephen Paddock.

And NBC reported today that Paddock also searched for hotels near Boston's famous baseball field, Fenway Park.

Paddock booked a room at a Chicago hotel on the weekend of the Lollapalooza music festival some two months before he opened fire on a country music concert in Las Vegas from a 32nd-floor room of a hotel and killing 59 people, an official says.

The official said police had found no evidence Paddock ever went to Chicago during the weekend of Lollapalooza - a music festival that attracts hundreds of thousands of people including, this year, the oldest daughter of Barack and Michelle Obama.

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Lorde was a headline act at Lollapalooza, as she was at the Life is Beautiful event in Las Vegas in September - another music festival for which Paddock had booked accommodation overlooking the venue.

Lorde performed at Lollapalooza briefly before wild weather ended her set early.

TMZ reports that Paddock would have had a similar view to the one he had of the Route 91 Harvest country music festival in Las Vegas where he killed at least 59 people.

About 400,000 people, including Barack and Michelle Obama's oldest daughter, Malia, attended the festival, which also showcased artists like The Killers and Muse.

The official, who was not authorised to discuss the investigation of Paddock's movements, spoke only on condition of anonymity after being briefed on the investigation.

The Blackstone Hotel in Chicago, where Paddock made the reservations, overlooks the main stage and other stages at Grant Park where the music festival is held every year.

Paddock's booking of the hotel room, first reported by TMZ, comes as investigators, trying to determine a motive for the Las Vegas shooting, have been trying to track Paddock's movements in the days before he opened fire from the Mandalay Bay casino resort on Sunday night.

Air Force One departs Las Vegas past the broken windows on the Mandalay Bay hotel, where shooter Stephen Paddock conducted his mass shooting along the Las Vegas Strip. Photo / Reuters
Air Force One departs Las Vegas past the broken windows on the Mandalay Bay hotel, where shooter Stephen Paddock conducted his mass shooting along the Las Vegas Strip. Photo / Reuters

Unlike many other mass killers, Paddock led such a private life that no one seemed to know him well, and those who did had no sense he was capable of gunning down 58 people and injuring hundreds more before killing himself.

Meanwhile, Boston's police commissioner says he will contact federal investigators about a report that the Las Vegas shooter researched locations in Boston, including hotels near the city's Fenway Park baseball stadium. Few, if any, hotels have views of the grandstands.

But William Evans said Thursday he could not confirm the report and had not been briefed on the matter

Massachusetts Gov. Charlie Baker also says he's aware of the reports but could not discuss them because of the ongoing investigation into the mass shooting.

Baker said that police officials based in Boston were "fully plugged in" to the investigation and were in contact with Las Vegas authorities

FBI Deputy Director Andrew McCabe said he was surprised Paddock had provided so few clues, and that has proved challenging.

Clark County Sheriff did share on Wednesday night said Paddock had rented a Los Vegas apartment in another high-rise above another music festival a week earlier, though he could not say why.

He said he felt it was unlikely Paddock could have pulled off the elaborate plan alone, though investigators have no idea who may have helped him.

- AP, AAP