, renamed the Isabella Joy Thallas Act in honor of a 21-year-old woman who was shot and killed in Denver in 2020, requires a gun owner to report their lost or stolen firearm within five days or be subject to fines. The second, House Bill 1106 , mandates that gun owners “responsibly and securely” store their firearms when not in use to prevent juveniles and other unauthorized users from accessing them. It also requires a licensed gun dealer to provide a locking device with each firearm sale or transfer. Both bills had previously been under discussion, but the March 22 mass shooting at a King Soopers supermarket in Boulder that left 10 dead created a greater sense of urgency, Polis said in a news conference.