"I am selling dark history," Holler says. He insists that his business also has social value, in that it allows experts to examine works of art and letters to analyze the minds of criminals – and perhaps prevent future crimes.
Andy Kahan, director of the Mayor's Crime Victims Office in Houston – and the man who coined the term "murderabilia" – has been fighting against the open market for such items for 14 years. He first became involved in the field as an active buyer in order to research the subject. The murderabilia industry has grown by "leaps and bounds" over the years, Kahan says, because it is fed by the accessibility of the Internet.
As part of his victims' rights advocacy, he shows his audiences serial killers' hair or fingernail clippings, both of which were bought online, he says. He isn't opposed to collecting, but he believes any money made from the sale of true-crime collectibles should go only to victims' families. In 2011, for instance, the government auctioned items that belonged to Ted Kaczynski, "The Unabomber," a mathematician who sent letter bombs during a 20-year period, killing three. Proceeds went to victims and their families.
Murderabilia vendors aren't alone in profiting from murder, counters Holler, who is 44 and works out of his home in Jacksonville, Fla. His business is no different than selling true-crime books or profiting from documentaries, movies or entire networks devoted to murder, he says.
In Milwaukee, visitors can take a 90-minute tour of where Jeffrey Dahmer,"The Milwaukee Cannibal," stalked and killed seven of his 17 victims. His crimes involved rape, murder, dismemberment and cannibalism.
The National Museum of Crime & Punishment in Washington, D.C., displays items serial killers have owned and weapons they have used. Janine Vaccarello, chief operating officer of the museum, says there is a distinction between an open market for true-crime collectibles and displaying items in a museum.
"Our mission is to educate, to tell our nation's history of crime and punishment and also to show how we have formed laws through the years," she says. "The impact of seeing the photos and objects leaves a profound impression."
Vendors of murderabilia insist felons aren't profiting, but Kahan says he has found evidence to the contrary.
"You shouldn't be able to rob, rape and murder and make a buck off it," he says. He also says he has seen people misrepresenting themselves to serial killers in letters as fans or groupies in order to obtain items to sell.
Crafting legislation to curb the murderabilia market has been difficult and mostly unsuccessful. On Sept. 25, a bill was re-introduced in Congress for the third time by Sen. John Cornyn, R.-Texas, to combat the sale of murderabilia. The law is meant to ban a specific list of criminals from sending anything outside of prison by mail.
Forty states and the federal government also have passed "Son of Sam Laws," which are designed to prevent felons from benefiting financially from their "celebrity" status and to divert money to victims' families, Bonn, the criminologist, writes in his book.
"When you commit extremely violent crimes, you lose certain rights and privileges. One of them is the ability to tell your story," he writes.
Sometimes the laws face issues with freedom of speech, however. In 1991, the U.S. Supreme Court voted unanimously that New York state's law was inconsistent with the First Amendment.
"Having true freedom of speech means protecting not just speech we like; the First Amendment's protections apply equally to unpopular speech and unpopular speakers," says Lee Rowland, staff attorney with the American Civil Liberties Union's Speech, Privacy and Technology Project.
Victims' rights advocates, however, say the murderabilia market poisons the memory of the victims, who often are forgotten in the face of violent crimes.
"From a victim's perspective there is nothing more nauseating and disgusting than finding out the person who murdered one of your loved ones now has items being hawked by third parties for pure profit," Kahan says.