Police on Tuesday struggled to establish the motive behind the Las Vegas concert massacre as the city began the process of recovering from one of the deadliest mass shootings in US history which claimed 59 lives and left another 527 people injured.
Gunman Stephen Paddock, 64, stationed himself in a 32nd-floor luxury suite of the Mandalay Bay Resort and Casino on Sunday evening and fired into a crowd of thousands of people attending singer Jason Aldean's concert. He was later found dead in his room at the hotel.
The police said the shooter had stockpiled a total of 42 firearms in his hotel room and at his home, 130 km away from the site of the massacre, CNN reported.
Authorities retrieved 19 weapons from his home in Mesquite, a small city in Nevada, and 23 in the hotel room. He also had in his possession two other devices that could transform his semi-automatic weapons into automatic ones.
Explosives, several thousand rounds of ammunition and "electronic devices" were also found from Paddock's home, Clark County Assistant Sheriff Todd Fasulo said.
Police found in the gunman's car several kilos of ammonium nitrate, a substance used in the manufacture of explosives. But no clear reason for the killings was established.
The federal authorities said there were no indications that Paddock had ties to any international terrorist organisation and never faced any notable criminal charges, despite a claim from the Islamic State for the attack.
Some investigators said Paddock had a history of mental illness, but there was no confirmation of this.
Trump described the gunman as a "very, very sick individual". A nurse, local government workers and student were among victims identified from across US and Canada as families voiced grief on social media.
A registered nurse from the US state of Tennessee and a man from Maple Ridge, British Columbia, were among the first identified victims of the shooting.
Sonny Melton, 29, who lived in Big Sandy, Tennessee, and worked at a nearby hospital, died while shielding his wife from bullets when the shooting began.
The Canadian Broadcasting Corporation reported that a 23-year-old British Columbia man, Jordan McIldoon, was also among the dead. Rest of the identified victims were from the US.
With hundreds of victims still hospitalised, officials said the death toll was likely to rise.
The shooter spent his last moments firing desperately at the police through the door of his room at the hotel, said Clark County Sheriff Joseph Lombardo.
He also fired at a security guard and a SWAT team, comprising six agents, who were combing the floors of the hotel looking for him, and killed himself before he could be apprehended.
The killer's brother, Eric Paddock, said he was "in shock, horrified, completely dumbfounded".
Several vigils were held on Monday night to honour the victims of the shooting. Communities came out in Reno, Las Vegas and at the campus of University of Nevada.