A man who killed four people at a Manhattan office building bought the rifle he used in the attack and the car he drove across country from his supervisor at a Las Vegas casino, authorities said Wednesday.

In 2022, Nevada enacted a ban on ghost guns, which are firearms without serial numbers that are sold as kits that users assemble on their own. It is one of 15 states that created legislation regulating those weapons, which law enforcement has flagged as untraceable.