The shooter who killed 58 people at a country music festival in Las Vegas before turning the gun on himself initially planned to escape, US authorities said late on Wednesday night.
Clark County Sheriff Joseph Lombardo told reporters that there was evidence Stephen Paddock planned on surviving the shooting and escaping, but declined to give further details.
Investigators are still stumped for clues as to why the 64-year-old opened fire on Sunday evening from the 32nd floor of the Mandalay Bay hotel on the Las Vegas Strip, wounding a revised total of 489 people.
"What we know is that Stephen Paddock is a man who spent decades acquiring weapons and ammo and living a secret life, much of which will never be fully understood," Lombardo said.
Lombardo added that Paddock may have had help since authorities find it hard to believe the shooter assembled his arsenal of weapons, ammunition and explosives by himself.
"You have to make an assumption that he had some help at some point," Lombardo said.
Note found in hotel room
The Clark County sheriff outlined other new details in the shooting, including:
— Paddock may have scouted the location by renting a room at the Ogden, a nearby hotel, during another music festival one week earlier.
— Investigators found a note in the room where Paddock carried out the shooting. Lombardo did not elaborate on its contents, but said it was not a suicide note.
— Police found 1,600 rounds of ammunition and 50 pounds (23 kilograms) of an explosive used in target shooting in Paddock's car.
Girlfriend didn't know about massacre plan
Paddock's girlfriend said on Wednesday she had no idea that he was plotting a massacre when he asked her to visit family in the Philippines.
Marilou Danley, who has been called a "person of interest" by investigators, issued the statement after returning to the US from the Philippines and being interrogated by the Federal Bureau of Investigation (FBI) agents.
"I knew Stephen Paddock as a kind, caring, quiet man," Danley said in a statement read by her attorney. "He never said anything to me or took any action that I was aware of that I understood in any way to be a warning that something horrible like this was going to happen."
She said she was initially pleased when Paddock wired her $100,000 (€85,000) in the days before the shooting but she later feared it was a way to break up with her.
"It never occurred to me in any way whatsoever that he was planning violence against anyone," Danley said.
Some Republicans ready to talk about gun control
The shooting has relaunched the ongoing debate in the US about gun laws, which tend to not be restrictive.
Some senior Republicans in Congress have even expressed a willingness to discuss some gun control measures — specifically legislation that would ban "bump stocks" like the ones used by Paddock in the Las Vegas shooting.
Republican Texas Senator John Cornyn said he had spoken with Judiciary Committee Chairman Chuck Grassley about convening a hearing on the matter.
"If somebody can essentially convert a semi-automatic weapon by buying one of these and utilizing it and cause the kind of mayhem and mass casualties that we saw in Las Vegas, that's something of obvious concern that we ought to explore," Cornyn told reporters.
The devices, known as "bump stocks" are legal in the US and were originally intended to help people with limited hand mobility more easily fire semi-automatic rifles. The device can increase a rifle's firing rate from 45 and 60 rounds per minute to between 400 and 800 rounds per minute.
rs/msh (AP, dpa, Reuters)