Details emerging from Stephen Paddock's Las Vegas hotel room have revealed the extent of the gunman's meticulous planning and potential signs the hotel may have missed.
Pictures from the scene show the 64-year-old's body next to his weapons and spent ammunition. On the table next to him is what appears to be a note, written on pink paper.
While the existence of a note and its potential contents are yet to be confirmed by police, hotel staff have revealed the retired accountant kept a "Do Not Disturb" sign on his room for days before carrying out the massacre.
It's also emerged Paddock had been collecting guns since 1982 and bought 33 guns in the last year, including one the day he checked into the hotel.
Jill Snyder, the special agent in charge at the Bureau of Alcohol, Tobacco and Firearms, told CBS he bought 33 firearms, mostly rifles, between October 2016 and September 28 this year.
Guns and Guitars general manager Christopher Sullivan said he felt "physically sick" from the knowledge but denied doing anything wrong.
"We do everything right, we can't control what someone does once they leave this store," he said.
'DO NOT DISTURB'
An employee told the New York Times housekeepers are only allowed to enter rooms with a sign on the door in the presence of a security guard - which rarely happens and only after several days.
A security source told Fairfax, it was a breach of policy not to check on the guest after 24 hours of such a sign being displayed. Paddock also reportedly asked for an upgraded room for a "better view".
"There were a number of missed opportunities by the hotel," the official said. "These things in isolation don't seem much but when you put them all together, they raise serious suspicions."
It's also been revealed Paddock had stayed at the hotel three times before, raising the possibility he had been planning for the attack.
The 1705 square foot corner suite was found rigged with security cameras on the door, in a service cart and in the hallway. Paddock had also shot a security guard who had tried to approach, before taking his own life.
By the time of Sunday night's attack, he would have been in the room for three days watching the festival unfold just 500 metres away. Police are reportedly investigating whether he planned an earlier attack.
Clark County Sheriff Joseph Lombardo said the shooting was "obviously premeditated" and Paddock "evaluated everything he did". That includes disguising the 23 weapons he had in the room from hotel staff.
"It has been determined that he had hotel employees going to and from his room and nothing nefarious was noticed," the sheriff said.
The background and motives of Paddock are a key target for police investigations. The so-called "blank slate" has been described as unusual in terms of mass killers as he is older than average and has left no online footprint in terms of his motives or mental state.