LAS VEGAS (CBSNewYork/AP) — The gunman behind the deadliest mass shooting in modern U.S. history led a “secret life” that has so far thwarted investigators trying to figure out a motive for the attack.

As CBS2’s Jessica Moore reported, purses and shoes lay among overturned chairs and debris at the site of the Route 91 Harvest Festival Thursday, four days after the shooting. Meanwhile, investigators continued to comb through Paddock’s life and hotel room, trying to figure out why he carried out the Sunday night massacre.

READ MORE: Judge Lifts Temporary Pause On Vaccine Mandate For NYC Teachers And Other City Workers, Who Now Must Be Vaccinated By Monday

“We don’t have any immediately accessible thumb prints that would indicate the shooter’s ideology or motivation,” said FBI Deputy Director Andrew McCabe.

It has been a massive, widespread investigation as law enforcement are still putting together a working timeline of Stephen Paddock’s final hours.

Las Vegas Shooting: Latest | Photos | Videos | The Victims

“More than 100 investigators have spent the last 72 hours combing through the life of 64-year-old Stephen Paddock to produce a profile of someone I will call disturbed and dangerous,” Clark County Sheriff Joseph Lombardo said.

Authorities now say Paddock tried to escape from Mandalay Bay after the mass shooting, but also say he left a note before taking his own life. It was not a suicide note, and the content was unknown.

The sheriff said Paddock was a man “who spent decades acquiring weapons and ammo and living a secret life, much of which will never be fully understood.”

Based on the number of guns and the amount of ammunition found in Paddock’s hotels suite and one of his homes, police now believe he may not have been planning the attack alone.

“You’ve got to make the assumption he had to have some help at some point,” Lombardo said.

The No. 2 official in the FBI said Wednesday he was surprised investigators had not uncovered more.

“There’s all kinds of things that surprise us in each one of these events. That’s the one in this one, and we are not there yet,” McCabe said. “We have a lot of work to do.”

In an effort to try to crack Paddock’s state of mind, the FBI spent hours on Wednesday interviewing his longtime girlfriend, who returned Tuesday from a weekslong overseas trip. She said she had no inkling of the massacre he was plotting when he sent her to see family in her native Philippines.

“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,” Marilou Danley, 62, said in a statement read by her lawyer outside FBI headquarters in Los Angeles.

She confirmed he wired her money while she was overseas, but said she thought he was preparing her for a break-up.

“It never occurred to me in any way whatsoever that he was planning violence against anyone,” she said in a the statement read by her lawyer.

Investigators said Paddock amped up stockpiling weapons last fall, amassing 33 guns within 12 months.

Lombardo said Wednesday that Paddock had 1,600 rounds of ammunition and several containers of Tannerite, an explosive commonly used in target shooting, that totaled 50 pounds in his car. But it wasn’t clear what, if anything, Paddock planned with the explosives, he said.

Paddock, who set up surveillance cameras in his room and to see anyone approaching outside, also had an escape plan, Lombardo said, though he fatally shot himself as police closed in on his luxury suite on the 32nd-floor of the Mandalay Bay resort casino.

Lombardo declined to say what led authorities to believe he planned an escape but said he might have were it not for a hotel security guard who showed up in the hallway outside his suite.

“His bravery was amazing,” Lombardo said. “He remained with officers providing key pass to access rooms and actually continued to help them clear rooms.”

READ MORE: NJ TRANSIT Bus, Car Crash In Irvington Takes Out Utility Poles

Investigators also revealed that Paddock had rented a condo at The Ogden building in downtown Las Vegas overlooking the site of the Life is Beautiful music festival back in September.

CBS News also reported Chicago Police confirmed that Paddock made reservations at the Blackstone Hotel in downtown Chicago on the weekend of the four-day Lollapalooza music festival in Grant Park – which the hotel overlooks. The festival typically brings about 100,000 people a day to the park.

As CBS2’s Jessica Layton reported, Chicago Mayor Rahm Emanuel said the 40th Bank of America Chicago Marathon this coming Sunday will go on with unprecedented security.

“It’s the right thing to do, and people will not only find it rewarding, we’ll show what we’re made of,” Emanuel said.

There were also reports that Paddock may have been scouting Fenway Park in Boston.

Paddock had no known criminal history. Public records contained no indication of any financial problems, and his brother described him as a wealthy real estate investor.

Paddock was prescribed Valium this summer for anxiety and investigators are now looking into whether mental health played a role and whether Paddock fits the clinical description of a psychopath, CBS2’s Moore reported.

Former FBI profiler Mary Ellen O’Toole said Danley may be able to provide investigators with critical clues about Paddock’s mental state, and more importantly about the issue of whether he was a psychopath.

A psychopath, O’Toole explained, is “someone who has no guilt for what they do; someone who can be very controlling and dominating, and I’d walk (Danley) through those personality traits to see if those sound at all familiar to the man that she knew.”

At last check, 50 of the hospitalized victims remained in critical condition, and local police said the number of fatalities may go up.

Lombardo on Wednesday also revised the death toll to 58 victims plus the shooter. The number of those injured has also been revised down to 489 from 527.

“Some of those patients were double counted or they were misconstrued as event injuries versus other injuries such as car accidents,” he said.

At last check, 50 of the hospitalized victims remained in critical condition, and local police said the number of fatalities may go up.

Countless people at the country music festival Sunday showed their own true colors by saving strangers. On Thursday, Justin Uhart and Jan Lambourne hugged in a hospital room.

Uhart, a bartender, stayed at the Canadian woman’s side after she was shot in the abdomen.

“I promised I wouldn’t leave,” Uhart said.

“If it wasn’t for him, I would not be here,” Lambourne said.

President Donald Trump and first lady Melania Trump met privately with victims at a Las Vegas hospital Wednesday and then with police officers and dispatchers, praising them and the doctors who treated the wounded.

“Our souls are stricken with grief for every American who lost a husband or a wife, a mother or a father, a son or a daughter,” he said. “We know that your sorrow feels endless. We stand together to help you carry your pain.”

MORE NEWS: Mattress Giveaway In Queens Highlights Depth Of Need That Remains 3 Weeks After Ida

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)