A new lawsuit filed overnight blames gun manufacturers and dealers for the deadliest mass shooting in modern U.S. history. In October 2017, a gunman opened fire on an outdoor concert in Las Vegas, killing 58 and wounding nearly 500 others. Among the victims who were killed was 31-year-old Carrie Parsons -- and only on "CBS This Morning," Parsons' parents explain why they're now suing the makers of the military-style rifles used in the attack and the dealers who sold them.



In the fall of 2017, Carrie Parsons flew to Las Vegas. "She was on top of the world. She'd just gotten engaged, so excited …" said her father, Jim. "Her business career was goin' great."

"I had been given my assignments, my mother-of-the-bride assignments, that I was supposed to start looking at venues," added her mother, Ann-Marie.



But while Carrie's excited parents planned for a wedding back home, a gunman opened fire on their daughter and thousands of others at a country music festival.



"That first day when I got there, they had us in a room …" Ann-Marie said. "And then finally I saw them coming down the hall, and it was an army of doctors, and at the very back was a person in a clerical collar. And they didn't even have to tell me."

Ann-Marie added that the only reason it was possible for a shooter 32 stories up and hundreds of yards away to fire a fatal shot is "the power of these weapons."



"These are weapons of war…" Jim added. "So you don't have to be a marksman to shoot 300 or 600 yards. He didn't target anyone, he just mowed 'em down. They didn't have a chance."



As the Parsons later learned, the shooter had used a dozen different rifles, each modified to simulate a machine gun with automatic fire. That allowed him to fire more than a bullet a second.



Machine guns have been banned since 1986. But the lawsuit the couple filed last night claims a gun that's easily modifiable to fire automatically is a machine gun, and is therefore "flatly illegal" under federal and state law. The suit names 16 defendants: the makers and sellers of guns used in the Las Vegas massacre. The companies named in the suit either declined or did not respond to CBS News' request for comment.

Josh Kosoff, the couple's lawyer, said that "the problem is, you're selling a machine gun by law." When asked about the idea that "guns don't kill people, people kill people," Kosoff said that "my answer is people kill people with guns."

"The amount of firepower that rained down on those concertgoers on October 1 could not have occurred without an AR-15 … modified by a bump stock to boot, because it just dumped out so much lead, and for such a prolonged period of time," Kosoff added. "That kind of firepower is what killed Carrie."



No one has ever won a lawsuit of this kind against a gun manufacturer, in part because a 2005 law protects the manufacturers against lawsuits when their product is used for criminal purposes. But for the Parsons, the suit is about justice for their daughter and hitting the gun industry where it hurts.



"How are they gonna reconcile when they're 85 years old, and on their death beds, all the devastation that they have helped happen to families?" Ann-Marie said.