James B. Grinder

James B. Grinder (1945–2010) was an American serial killer and rapist who murdered three teenage girls in Arkansas and a woman in Missouri between 1976 and 1984.

However, authorities still had little evidence tying Grinder to the murders, so they used a technique known as brain fingerprinting to help prove his guilt.

[2] On December 2, 1976, Grinder picked up Teresa Williams, 13, Crystal Donita Parton, 14, and Cynthia Mabry, 13, outside Russellville, Arkansas.

About a week after the murders, Grinder returned to the cemetery to cover Williams and Parton's remains with more brush.

Grinder told investigators that he saw the girls hitchhiking and picked them up, but he dropped them off at the interstate exit for Pottsville.

Helton's parents filed a missing persons report after she failed to come home from a party in New Cambria the night before.

Grinder had long been a suspect in Julianne Helton's murder, but police could not find enough evidence to arrest him.

Grinder sat in front of a computer screen with the device strapped to his head while Farwell asked him questions about the crime.

[4] Six days after the brain fingerprinting test, Grinder pleaded guilty to Julianne Helton's murder and was sentenced to life in prison.