LAS VEGAS (AP) -- In an effort to find a hint of the Las Vegas gunman's motive, investigators are looking into whether he was with a prostitute days before the shooting rampage, a federal official said.
Authorities are also scrutinizing cruises Stephen Paddock took and trying to find some meaning behind a note with numbers written on it that was left in his hotel room.
In addition, the FBI announced Friday that billboards would be put up around the city asking anyone with credible information on last weekend's massacre at a country music festival to call authorities.
More about the deadliest mass shooting in modern U.S. history:
Investigators believe the 64-year-old Paddock hired a prostitute in the days leading up to the shooting and were interviewing other call girls for information, a U.S. official briefed by federal law enforcement officials said. The official wasn't authorized to discuss the matter publicly and spoke to The Associated Press on condition of anonymity.
The official also disclosed that Paddock took at least a dozen cruises abroad in the last few years, most of them with his girlfriend, Marilou Danley. At least one sailed to the Middle East.
Clark County Undersheriff Kevin McMahill said Friday at a news conference that examinations of Paddock's politics, finances, any possible radicalization and his social behavior have turned up little information on what led him to rain bullets on a crowd of country music fans Sunday from his 32nd-floor hotel suite, killing 58 and wounding hundreds before taking his own life.
Billboards set to go up around Las Vegas will urge anyone with information about the shooting to dial 1-800-CALL-FBI.
VICE PRESIDENTIAL VISIT
Vice President Mike Pence is scheduled to visit Las Vegas on Saturday to take part in a ceremony honoring the victims of last weekend's massacre.
City officials said Friday that the vice president will speak at an event set for 12:30 p.m. in the City Council chambers.
A community interfaith unity walk to City Hall will be held earlier Saturday.
Organizers plan to release a flock of doves after Pence's speech to commemorate each of the victims.
IS NRA PROPOSAL A TRICK?
Some gun industry experts say the National Rifle Association's push for "bump stocks" to be re-evaluated by the government after the Las Vegas massacre is little more than a ruse to stall any momentum for wider gun control.
Adam Winkler, author of "Gunfight: The Battle over the Right to Bear Arms in America," said the NRA "can throw a sacrificial lamb of bump stocks because they know that gun owners don't use them or like them."
The devices, originally intended to help people with disabilities, fit over the stock and pistol grip of a semi-automatic rifle and allow the weapon to fire continuously, mimicking a fully automatic firearm. Bump stocks were found among Paddock's arsenal in his hotel room.
It was not immediately clear whether President Donald Trump or Attorney General Jeff Sessions, who oversees the Bureau of Alcohol, Tobacco, Firearms and Explosives, could order it to re-evaluate its judgment about devices.
SECURITY GUARDS RETURN TO WORK
Many members of a private security firm that manned the Route 91 Harvest festival the night of the massacre are returning to work this weekend.
The Las Vegas branch of Contemporary Services Corporation stayed put Sunday when Stephen Paddock began shooting from the 32nd floor of the Mandalay Bay hotel casino. The unarmed security guards helped lift people over barriers, hid them behind pillars and under the stage, and funneled them to exits.
A 21-year-old CSC guard, Erick Silva, was among the 58 people killed. Two other CSC guards were wounded.
Supervisor Cheryl Metzler worked a UFC weigh-in Friday, her first event since the shooting. She says going back to work with a group she considers family is "the best therapy."