In California, a convicted murderer isn't supposed to make money off the crime.

That doesn't stop others from profiting, though, with convicts likely benefiting through illicit deals.

"Murderabilia," as Andrew Kahan calls it, is an industry that finds yet another way to victimize the families of murder victims.

"There's nothing more disgusting than to find out that someone who murdered your loved one is making money by selling items," said Kahan, a victim advocate from Texas who a decade ago launched a nationwide crusade to expose the practice.

Just this week he found pieces from Scott Peterson and Cary Stayner posted on online auction sites. They included four letters written and signed by Peterson from death row at San Quentin State Prison.

Likewise, there are signed letters, a drawing and other artwork by Stayner, whose artistic ability might secure him a place on a prison kitchen's refrigerator, but not, say, in San Francisco's DeYoung Museum.

"On death row, they either become religious or Rembrandt," Kahan said. "Apparently, (Stayner) hasn't turned into Rembrandt yet."

Still -- and as ghoulish as it might seem -- there is a segment of society that will buy hair samples, fingernail clippings, clothing swatches, scribblings, artwork or anything else that once belonged to Charles Manson, Richard "Night Stalker" Ramirez, Polly Klaas killer Richard Allen Davis, Wilseyville murderer Charles Ng and their ilk.

Kahan first became aware of this more than a decade ago after reading a story in an upstate New York newspaper about serial killer Arthur Shawcross. It detailed how the New York State Department of Corrections discovered that a broker paid Shawcross for artwork, which the broker then sold on eBay.

The practice violated New York's "Son of Sam" law enacted to prevent that very thing from happening. California later passed similar legislation. That California now leads the nation in high-profile murderers selling items illustrates the prison system's inability to monitor the likely deals cut between killers and those who sell their stuff.

By the time eBay banned such sales, other Web sites had popped up. Thus, what began as an underground market for the macabre has gone public, with at least six online sites selling collectibles linked to the worst of the worst.

When Kahan set out to combat murderabilia, he bought items online to better understand how the market worked, and he uses them in his presentations. He also sent letters to 20 serial killers -- including Henry Lee Lucas, Manson, Ramirez and David Berkowitz (also known as Son of Sam) -- to solicit their input. Berkowitz replied.

"He was shocked and upset that his letters were being sold without his consent," Kahan said. "He volunteered to help."

Berkowitz gave Kahan a prison insider's primer for developing working agreements with collectors and brokers.

"He let me know from behind the scenes how they worked out the contractual details," Kahan said. "Sometimes they work out deals where they receive part of the proceeds. Other times, my research indicates they're totally clueless. They're doing their artwork (as a form of prison recreation), and somebody else is getting the benefits."

As he began to publicize his crusade, Kahan received a letter from Manson family member Susan Atkins.

"She'd had stuff taken from her prison cell that was being sold at auction," he said. "She said, 'It makes me look callous and unremorseful, which I am not.' "

Atkins died two years ago.

Kahan also learned that Lucas, whose mother was among the 360 people he confessed to murdering (only three could be proved) in the 1960s, '70s and '80s, received magazine subscriptions in return for his murderabilia.

Kahan said he's never come across anything for sale that might or should have become evidence during a murder trial. Nor does he find counterfeit items for sale, simply because the competition would rat out anyone discovered putting fake stuff on the market.

He has found jury lists with names and addresses for sale on a Florida-based site.

"Lots of public documents get sold," he said. "An autopsy report on Nicole Brown Simpson. One would think that never would happen, yet somebody gets a copy, makes copies and sells them at $15 to $20 a pop."

As for the four handwritten letters by Peterson and Stayner's letters and artwork, it's reassuring to know that as of 4 p.m. Wednesday no one had met the $55 opening bid for Peterson's scribblings on murderauction.com.

Nor has anyone paid $339 (discounted from $550) to supernaught.com for a letter written while Peterson was a guest in the Stanislaus County Jail after being arrested in April 2003 for the murders of his wife, Laci, and unborn son, Conner.

Nor had anyone offered the asking price of $85 for Stayner's signed letter and original drawing, $105 or $185 for his two pieces of so-called artwork on murderauction.com, or any of his three signed letters ranging from $165 to $205 on supernaught.com.

All of those items were discounted as well. Hey, it's a tough economy.

Families must choose between rent, food, clothing, health insurance -- and a Stayner original.

Or not.

Jeff Jardine is a columnist for the Modesto Bee. Contact him at jjardine@modbee.com.