The gunman Stephen Paddock, police said, fitted 12 of his weapons with so-called bump-stock devices that allow semi-automatic rifles to operate as if they were fully automatic machine guns, which are otherwise outlawed in the US.
Authorities said his ability to fire hundreds of rounds per minute for 10 minutes from a 32nd-floor hotel suite was a major factor in the high casualty count of 58 people killed and hundreds wounded. Paddock, 64, killed himself before police stormed his suite.
The carnage on Sunday night across the street from the Mandalay Bay hotel ranks as the bloodiest mass shooting in modern US history, surpassing the 49 people shot to death last year at a gay nightclub in Orlando, Florida.
The influential National Rifle Association (NRA), which staunchly opposed moves to tighten gun control laws after the Orlando massacre and others, said on Thursday bump stocks, which remain legal, “should be subject to additional regulations.”
“Gun control is a failed policy. We’ve tried it and it is safe to say that it doesn’t keep people safe,” Chris Cox, executive director at the NRA’s Institute for Legislative Action, said on Fox News on Thursday.
“There needs to be an honest conversation about solutions that work and one of those solutions is to make sure the Second Amendment is supported and protected.”
Democrats were urging new legislation, as the shooting reignited the long-standing US debate over regulation of gun ownership, protected under the Second Amendment of the US Constitution.
The NRA called for the US Bureau of Alcohol, Tobacco, Firearms and Explosives to address bump stocks by regulation, rather than opening up the issue to the legislative process.
Senior Republicans also signaled they were ready to deal with the sale of bump stocks — an accessory gun control advocates regard as work-arounds to bans on machine-guns.
“Clearly that’s something we need to look into,” House Speaker Paul Ryan told radio talk show host Hugh Hewitt.
US Representative Steve Scalize, a member of the Republican House leadership who is himself a victim of gun violence, voiced concern that hasty congressional action to restrict bump stocks could lead to wider limits on “the rights of gun owners.”
“There are people who want to rush to judgment,” Scalize said in an MSNBC interview on Thursday.
US President Donald Trump, an outspoken proponent of gun rights during his campaign for the White House, suggested he was open to curbs on bump stocks.
Thousands of mourners turned out on Thursday for a candlelight vigil honoring a Las Vegas police officer and member of the Nevada National Guard who was among those slain at Sunday’s concert while he was there off duty.
Under a full moon in a grassy memorial park, a police honor guard including bagpipes paid tribute to Charleston Hartfield, 34, who is survived by his wife and two children.
The Las Vegas Review-Journal also reported on Thursday that organizers of a gun show scheduled for this weekend at the Eastside Cannery Casino had canceled the event, saying it did not seem “prudent” in light of Sunday’s tragedy.
Investigators remained puzzled at what drove Paddock, a well-off retiree and avid gambler, to assemble an arsenal of nearly 50 firearms, thousands of rounds of ammunition and a supply of explosives before opening fire on a country music festival attended by 20,000 people.
Reports emerged on Thursday that Paddock may have targeted other sites for attack in Chicago or Boston before the Las Vegas shooting. Paddock also researched locations in Boston, including Fenway Park, home of the Red Sox baseball club, NBC reported, citing multiple law enforcement sources.
Police in Boston and Chicago said they were aware of the reports and were investigating them.
Discerning Paddock’s motive has proven especially baffling as he had no criminal record, no known history of mental illness and no outward signs of social disaffection, political discontent or extremist ideology, police said.
Paddock’s girlfriend, Marilou Danley, 62, was questioned by the FBI on Wednesday and said in a statement she never had any inkling of Paddock’s plans.