The Las Vegas gunman Stephen Paddock may have planned other attacks including a possible bomb plot and his girlfriend reportedly revealed that he had developed mental health symptoms. The 64-year-old booked hotel rooms overlooking two other music festivals prior to the massacre which left 59 people dead.
It emerged that he booked a room at the 21-storey Blackstone Hotel in Chicago, Illinois, overlooking the Lollapalooza music festival although there is no evidence he went to the city.
He also rented an apartment in a 21-storey building in Las Vegas the week before the attack that overlooked the Life Is Beautiful festival, Clark County Sheriff Joseph Lombardo said.
FBI deputy director Andrew McCabe said there is still no further information on a motive, saying, according to Sky News: "We have a lot of work to do."
Investigators are looking at why he went on a weapon-buying spree the year before and have questioned his girlfriend Marilou Danley. Mail Online reported that she had told the FBI Paddock developed symptoms of mental health issues and would scream at night.
An ex-FBI official told the paper that Danley had said Paddock, 64, "would lie in bed, just moaning and screaming, 'Oh my God.'"
Investigators believe that he may have been in "mental or physical anguish", that official and another ex-FBI source told NBC News. Officers believe that he had help in assembling the arsenal of weapons, ammunition and explosives recovered by police.
On Thursday 5 October, the powerful National Rifle Association (NRA) appealed to US regulators to consider "additional regulations" on the rapid-fire device used by the Las Vegas gunman.
The NRA says the use of 'bump-stocks' needs to be reconsidered and said in a statement: "Devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations."