“Guns don’t actually kill people” is sometimes a refrain from gun rights advocates when they run low on arguments in a policy discussion. On an incredibly basic level this is true. A gun itself is no more responsible for a death than a knife or an axe or any other instrument meant to harm and kill; the blame for a death falls on the person wielding them. But in the category of modern weapons–especially guns–the make, model and accessories matter a great deal.

When James Holmes allegedly stormed into a movie theater in Aurora, Colo. to maim and murder as many people as possible, he reportedly wielded an AR-15-type assault rifle. Holmes added an accessory: a 100-round drum that looks like two small film reels attached to the bottom of the weapon. This addition allowed him to fire round after round without reloading, which is what he allegedly did until the weapon jammed.

To produce this week’s cover, TIME commissioned Bartholomew Cooke, a talented young photographer who specializes in capturing the power of inanimate objects. When TIME asked Cooke to photograph the types of weapons—an assault rifle, two pistols and a shotgun—that were allegedly used in the massacre at a movie theater in Aurora, Colo., there were several difficult considerations. Cooke had photographed weapons before, but not in the connotation of a horrific tragedy. “It was important that I didn’t want to glamorize them, but I still did want to create a compelling graphic image,” Cooke says. “Figuring out how to photograph the gun was difficult. I certainly wouldn’t want images I create to cause anyone pain in any way.”

Bartholomew Cooke is a photographer based in Los Angeles and a regular contributor to TIME. See more of his work here.