LAS VEGAS – The Bureau of Alcohol, Tobacco and Firearms said the man responsible for murdering 59 people in Las Vegas on Sunday night purchased some of his 47 firearms in Texas.

In a news conference on Tuesday night, the ATF said agents from Dallas, Los Angeles, Phoenix and Boston have joined the investigation into Stephen Paddock’s massacre.

The 47 firearms were discovered after search warrants were executed in Paddock’s hotel room at the Mandalay Bay and his homes in Mesquite and Reno, Nevada. The weapons were purchased in California, Nevada, Texas and Utah, according to the ATF.

Investigators said there were 12 volleys of gunfire on Sunday night spread over nine to 11 minutes; all of it aimed at concertgoers attending the annual Route 91 Harvest Festival across Las Vegas Boulevard.

The first call for help came in at 10:08 p.m., police said. The gunfire stopped at 10:19 p.m.

Several police officers were working at an event inside the Mandalay Bay Hotel and formed their own team to clear guests away from danger, investigators said.

This afternoon, Clark County, Nevada Sheriff Joe Lombardo revealed that Paddock had a small camera positioned on a room service tray outside his room and a second camera attached to the peephole to warn him if officers were closing in.

For a city often defined by celebration, anguish is an emotion unfamiliar to Las Vegas.

“Just sitting at the casino last night eating at the restaurant and somebody’s slot machine went off with the TICK, TICK, TICK,” recalled Johanna Ernst, fighting back tears. “I thought I was going to die and die alone with nobody by me.”

She was at that concert Sunday night and still wears her wristband.

“Until everybody is out of the hospital, I’m going to keep it on. Just pray for these people,” Ernst explained.

Behind Las Vegas’ veneer, evidence remains of the terror that happened here. Thirty-two floors up at the Mandalay Bay, two windows are still shattered from where Paddock opened fire.

On the ground, the FBI took over Tuesday documenting the scene and just a couple hours ago, police reopened the southbound stretch of the strip closest to the crime scene.

“I think we have to get ahead of these issues, and there is a way if we look for the warning signs,” said Wayne Nance, who has studied mass shootings and profiled killers.

Forty-eight hours after the massacre, there’s still no motive. What provoked Stephen Paddock, a 64-year-old real estate investor, to commit mass murder?

The search for physical clues will wind down soon, but the search for answers will not.