Speed Freak Killer" Wesley Shermantine links his partner in crime Loren Herzog to more murders and says he also trained up a killing "apprentice," in a letter he sent from death row

Speed Freak Killer" Wesley Shermantine links his partner in crime Loren Herzog to more murders and says he also trained up a killing "apprentice," in a letter he sent from death row to KTXL-TV in Sacramento, Calif.

Shermantine, who is believed to have killed as many as 20 people with Herzog, has been sketching maps showing the location of victims' remains and giving them to Sacramento bounty hunter Leonard Padilla in return for payment.

The killer's information helped California police find the remains of Cynthia Vanderheiden, who disappeared in 1998, aged 25, and Chevelle "Chevy" Wheeler of Stockton, Calif., who went missing in 1985, aged 16. They also found more than 1,000 bones and bone fragments buried in a well.

In his latest letter, Shermantine claims that DNA tests on the other remains will show they belong to JoAnn Hobson, a 16 year old who disappeared in 1985, and a pregnant black woman, who he claims Herzog dumped with help from members of the Hells Angels.

Herzog, who killed himself earlier this year, also killed a hunter in Utah in 2004, according to Shermantine.

Shermantine, currently on death row in San Quentin jail, describes how Herzog wanted to join the Hells Angels and needed to build up a reputation, so he began training an apprentice named "Jason Jones," who he taught to kill without being detected.

He says he warned Jones to leave the country before any more burial sites were uncovered.

Shermantine, who claims he is not a killer, explains how he will not reveal any more burial sites because he has not been paid by Padilla.

He also criticizes the police search for bodies and the excavation of the well, claiming police "just crushed, busted the bones all to pieces."

Authorities believe Shermantine and Herzog killed up to 20 people in a drug-fueled killing spree in the 80s and 90s.

They were both jailed but Herzog was released in 2010 after an appeals court ruled investigators illegally coerced his confession. Herzog killed himself in January after Shermantine began revealing the burial places of victims.