A six-vehicle crash described as a “mass-casualty traffic collision” by police left at least nine people dead in Las Vegas, said officials. “We have not seen a mass-casualty traffic collision like this before,” Alexander Cuevas, with the North Las Vegas Police, told reporters on late Saturday. On Saturday evening, a Dodge Challenger ran a red light on Commerce Street and hit several vehicles at a “high rate of speed,” said Cuevas. He cited a bystander who witnessed the crash. “And, with that, it struck multiple vehicles and, unfortunately, it was a chaotic event,” Cuevas said, adding the collision involved some 15 people. Nine died and six suffered injuries, the officer said. “Please make this a safer community by slowing down. Pay attention to speed limits,” he added. North Las Vegas Police told The Associated Press that the identities of the driver and the other eight people who died would be released …