(Newser) – The Dark Knight massacre at an Aurora theater has had an "insane" effect on gun sales in Colorado, says an employee of one gun store, where 15 to 20 people were waiting outside when it opened Friday morning after the shooting. Background checks for people attempting to purchase firearms in the state are up more than 41% since the shooting, and there is also increased interest in concealed-carry permits, the Denver Post reports.

The store's basic gun class is booked solid for three weeks straight, which is unusual, the employee says, adding, "When it happens in your backyard, people start reassessing—'Hey, I go to the movies.'" Another course, which is required to obtain a concealed-carry permit, is overbooked. Similar increases were seen in Arizona after Gabrielle Giffords' shooting, and in Virginia after the Virginia Tech shootings. (Read more Aurora, Colorado stories.)

