It's known as "murderabilia" —the sale of the letters, possessions and mementos of famous criminals to collectors.
Now it includes the letters and drawings of Linda Ann Weston, who allegedly kept mentally disabled adults captive in a Tacony home and allegedly starved two to death while collecting their benefits checks.
"I will be the first to admit that I am a 'modern day smut peddler,'" said Kelly Hutchison, a San Diego artist who runs DarkVomit.com, a True Crime Museum and Prison Art Gallery, where the Weston collection is being sold, via email.
Hutchison won't say how much he paid, which are for sale for $65 to $85 each.
He said a "pen pal" of Weston's who is studying social services at college sold him the letters — which Weston purportedly wrote and sent from prison within the last few months, along with drawings.
One shows Jesus. Another shows one of the Seven Dwarfs masturbating.
"I do find the art and letters of Linda's to be quite fascinating," Hutchison said. "Her handwriting is childlike and her writing is very erratic. The drawings that she includes with her letters do not make any sense and they are so bizarre and weird."
Weston's defense attorney, Patricia McKinney, criticized the sale.
"No matter how low the bar is set for capitalizing on the mentally ill, it doesn't surprise me that someone is always willing to go lower," McKinney said. "It's also interesting that there is no way of authenticating these at all."
Weston and three others, including her daughter, were arrested in October 2011 after four adults were found captive in their basement, as well as Weston's niece, whom she was fostering for DHS.
Weston is charged with murder for the deaths of two mentally disabled women whom she allegedly kept captive at other locations.
She is pleading insanity, but the feds say she masterminded the scheme for profit. Prosecutors are considering seeking the death penalty against Weston.
"After researching her case further ... it almost appears that she is going out of her way to sound and look 'crazy' in these letters, [or] else she is medicating on very serious drugs," Hutchison said.
Killers don't make money off murderabilia.
Possessions of celebrity murderers like David Berkowitz, Ted Bundy and John Wayne Gacy have been sold, usually through a third party, such as a relative or prison guard, to a collector who resells the goods.
Around Philly, murderabilia has included dirt from the basement of serial killer Gary Heidnik, for $40 a bag with a certificate of authenticity.