A Pennsylvania woman jointly charged with murder with her husband has claimed she has killed at least 22 other people.
Nineteen-year-old Miranda Barbour made the claims in an interview with a newspaper while in prison.
Miranda and Elytte Barbour are currently charged with killing Troy LaFerrara after meeting him online.
As well as admitting that murder, she also claimed a six-year killing spree around the US.
She claimed it was part of an involvement in a satanic cult, that began in Alaska when she was 13, before moving to North Carolina.
Police say they are investigating the 19-year-old's claims and have contacted both the FBI and police forces in other states.
The couple, who married in North Carolina and moved to Pennsylvania about three weeks before the crime, are accused of murdering Mr LaFerrara after placing an ad in classifieds website Craigslist, offering companionship for money.
Prosecutors are seeking the death penalty for both defendants.
Lawyers for Ms Barbour and her husband, 22-year-old Elytte Barbour, have sought psychiatric evaluations for their clients.
Police claim Mr Barbour told investigators they committed the crime because they wanted to kill someone together.
The couple reportedly told police that Miranda Barbour stabbed LaFerrara in the front seat of her car while her husband held a cord around his neck.
Claiming responsibility for the 22 additional deaths, Ms Barbour told Sunbury's The Daily Item that "I feel it is time to get all of this out. I don't care if people believe me. I just want to get it out."
She said she had no remorse and only killed "bad people," although she offered little detail on the murders she claimed to have participated in in Alaska, Texas, North Carolina and California.
Online records for the woman the newspaper identified as Barbour's mother, show her as having lived in both Alaska and North Carolina.