As victims of one of the worst mass shootings in American history continue to recover from their wounds, gun sales have spiked in Colorado and other parts of the United States.

Fearing the possibility of tighter government controls on firearms in the wake of the movie theatre shooting in Aurora, Colo. on Friday, an increasing number of people have been purchasing guns in Colorado and other states, including Florida, Georgia, Washington.

In the three days following the shooting at The Dark Knight Rises premiere that killed 12 people and wounded 58 others, the state of Colorado approved 2,887 background checks for people wanting to buy a gun — 25 per cent higher than average for a Friday to Sunday time period and a 43-per-cent increase from the same time period a week earlier.

The owner of Gunners Den in Arvada, Colo. described demand for his concealed weapon training certification as “off the hook” — the course is required for certification for a concealed-weapons permit in the state.

King County in Washington state has seen almost twice as many requests for concealed pistol licenses compared to the same time last year. Background checks in Florida were up 14 per cent on Friday compared to the week before.

Oregon and California reported increases of 11 and 10 per cent, respectively, compared to the previous month.

And the owner of Adventure Outdoors in Smyrna, Ga. said his sales were up 300 per cent in the wake of the shooting, compared to the same time last year.

Gun sales also spiked following the election of President Barack Obama, when firearms advocates feared he’d curtail gun rights. According to FBI figures, firearms sales also surged in Arizona after Rep. Gabrielle Giffords was shot in January 2011.

Some Democrats in Congress have proposed a ban on high-capacity ammunition magazines, but there appears to be little political will to tighten gun legislation.

The alleged Colorado gunman, James Holmes, made his first court appearance on Monday. He’s set to be formally charged next week.

Police allege Holmes began buying guns at stores in the Denver area two months before the attack and had received up to 50 packages in the past four months, delivered to his home and school. He allegedly ordered 6,000 rounds of ammunition online.

He’s accused of tossing gas canisters inside a cinema during a midnight screening and then firing on the audience. The gunman was wearing full body armour, a gas mask and a ballistic helmet, according to police.

Auhtorities allege Holmes had bought a semi-automatic rifle, two Glock pistols and a shotgun. He’s also accused of rigging his apartment with sophisticated booby traps.

With files from The Associated Press