LAS VEGAS (CBSNewYork/AP) — Investigators say Las Vegas gunman Stephen Paddock may have been looking to target other venues, and there are questions about what his girlfriend Marylou Danley really knew.

Investigators are working to reconstruct Paddock’s life in the days and months before the shooting, hoping to understand why he did it.

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CBS News has learned that Danley told the FBI that she was concerned about Paddock’s mental stability.

Some security analysts believe she knows more than she’s revealing, CBS2’s Mola Lenghi reported.

“She is giving little pieces of information at a time. She is really afraid to tell the truth and not being forthright because she is afraid she will get into trouble,” said CBS News Law Enforcement Analyst Paul Viollis.

Investigators say they aren’t sure Paddock acted alone. He is believed to have hired a prostitute in the days leading up to the shooting, and local call girls are now being questioned, The Associated Press reported.

“What we continue to investigate is whether anybody else may have known about this incident before he carried it out,” Las Vegas Metropolitan Police Undersheriff Kevin McMahill said Friday.

Paddock picked Vegas for his attack, but he reportedly had other targets in mind.

He booked rooms overlooking the Lollapalooza festival in Chicago in August and the Life Is Beautiful show near the Vegas Strip in late September, according to authorities reconstructing his movements before he undertook the deadliest mass shooting in modern U.S. history.

Fenway Park in Boston also came up during the investigation of Paddock, Boston police Lt. Detective Mike McCarthy said Thursday, though he provided no further details.

It was not clear if he contemplated massacres at the other sites.

The details came to light as investigators struggled to figure out why the 64-year-old high-stakes gambler opened fire on a crowd of 22,000 Sunday night from the 32nd floor of the Mandalay Bay hotel casino before taking his own life.

“While some of it has helped create a better profile into the madness of the suspect, we do not still have a clear motive or reason why,” McMahill said.

With all that in mind, police will be patrolling the hillside near the Rose Bowl while 60,000 music fans watch a Coldplay concert Friday night.

“We always worry about a copycat situation, no matter what incident occurred,” said Lt. Art Schute of the Pasadena Police Department.

Security measures are also being finalized for outdoor events in Memphis and Austin, Texas, where fans are being offered a refund if they have safety concerns.

The NYPD says outdoor concerts this weekend in Central Park are getting extra attention. The police presence was visible Friday night, with officers watching concertgoers closely as they filed into the venue.

“I like that. That’s a relief,” Stephanie Castro, of Washington Heights, said.

Those looking forward to the show said, sadly, the events in Las Vegas were on their minds.

“When things like that happen, you have to look for exits, you have to know which way you’re going to escape, just be aware,” Castro said.

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Additional police will also be on hand for the Chicago Marathon on Sunday.

Meanwhile, Las Vegas is paying tribute to those who have been killed. Fifty eight white crosses are now lining the Las Vegas strip in tribute to the concert goers killed during the rampage. The crosses will remain in place for 40 days.

All 58 victims of the Las Vegas massacre have now been identified.

The victims range in age from 20 to 61. The coroner’s office will be releasing the bodies to their families and Las Vegas officials have set up a family information center for families to assist with funeral plans.

On Thursday night, thousands raised candles and surrounded the widow and two children of Officer Charleston Hartfield, who was killed in the shooting.

Hartfield, a 16-year Army veteran who served in Iraq, was known as “Charles,” ”Chuck” and “ChuckyHart,” but one longtime friend and colleague dubbed him “Captain America.”

“Charlie Hartfield was the greatest American I have ever known,” Sgt. Ryan Fryman told the crowd.

His was among the first memorials for the dead.

Five days after the shooting, 8-year-old Brooke Patterson spoke with grace beyond her years at a vigil for her mother.

“She would just love to see everyone here today. She would love to see all your smiles,” she said.

“We were supposed to have a long time still together, and she wasn’t the one that was supposed to pass away first,” her husband, Robert, added.

Police announced Thursday that they had found a Hyundai Tucson SUV they had been searching for as part of the probe while executing a search warrant at the home in Reno that Paddock shared with his girlfriend, Marilou Danley. It wasn’t immediately clear if the car was found on Thursday or earlier in the week when police searched the home and found several guns and ammunition.

Paddock had an arsenal of 23 weapons in his hotel room. A dozen of them included “bump stocks,” attachments that can effectively convert semi-automatic rifles into fully automated weapons.

In a rare concession on gun control, the National Rifle Association announced its support Thursday for regulating the devices.

Paddock sent Danley on a trip to her native Philippines before the attack, and she was unaware of his plans and devastated when she learned of the carnage while overseas, she said in a statement.

Investigators combing through his background for clues remain stumped as to his motive.

Australian police are also assisting since, Danley became an Australian citizen after moving there and marrying a local man decades ago.

“There is obviously a lot of international interest in this investigation,” Australian Federal Police Commissioner Andrew Colvin said, “We should also be very confident that agencies are working very closely together.”

Las Vegas police are pleading with anyone who may have information from the months or weeks before the shooting to give them a call. They said they’re looking at every aspect of hislife from birth to death.

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