Joyce Gilchrist was a former forensic chemist who had participated in over 3,000 criminal cases in 21 years while working for the Oklahoma City police department, and who was accused of falsifying evidence. Her evidence led in part to 23 people being sentenced to death, 11 of whom have been executed. After her dismissal, Gilchrist alleged that she was fired in retaliation for reporting sexual misconduct. Gilchrist died in Texas on June 14, 2015. 
Gilchrist earned the nickname "Black Magic" for her ability to match DNA evidence that other forensic examiners could not. She was also known for being unusually adept at testifying and persuading juries, thus obtaining convictions. In 1994, Gilchrist was promoted to supervisor from forensic chemist after just 9 years on the job, but her colleagues began to raise concerns about her work.
Gilchrist was dismissed in September 2001 due to "flawed casework analysis" and "laboratory mismanagement". Concerns about Gilchrist's actions were first raised when a landscaper, Jeffrey Todd Pierce, who had been convicted of rape in 1986 largely based on Gilchrist's evidence despite a clean criminal record and good alibi, was exonerated based on additional DNA evidence.
Pierce, a husband and the father of two infant children, was misidentified in a police line-up. After voluntarily giving hair and blood samples to the police investigators in an attempt to clear his name, he was arrested and charged with the rape. Gilchrist claimed his hair samples were "microscopically consistent" with the hairs found at the crime scene. Pierce was cleared of the crime in 2001 after DNA evidence was re-examined, and released after 15 years in prison. Pierce subsequently filed a lawsuit against Oklahoma City, seeking $75 million and charging that Gilchrist and Bob Macy, a now-retired district attorney, conspired to produce false evidence against him. The suit was settled for $4 million in 2007, with one Oklahoma City councilman noting that the city could have had to pay much more.
Other cases from individuals convicted on Gilchrist's testimony continue to work their way through the courts.
- Michael Blair was sentenced to die for the murder of a young girl in 1993. The evidence leading to his conviction included shafts of hair found near the girl's body and in Blair's car. New DNA evidence showed that the hair matched neither the girl, nor Blair.
- During the early 1990s, Oklahoma state law did not allow defense attorneys to use government funds to hire other forensic scientists to verify Gilchrist's claims. However, during appeals of Malcolm Rent Johnson's death penalty case, two forensic experts hired by the defense were critical of Gilchrist's testimony, particularly as it relied upon several "blue-colored hairs" that seemed too "ubiquitous" to be useful evidence.
- Curtis McCarty was released in 2007 after spending nearly 20 years on death row. The courts found that Gilchrist acted to either alter or intentionally lose evidence. In 2009 McCarty's lawsuit reached a settlement in which Gilchrist was responsible for a payment of over $16 million, an amount that she is attempting to force Oklahoma City to pay.
Over 1,700 cases in which Gilchrist's evidence was significant to a conviction were reviewed by the state of Oklahoma. Gilchrist’s attorney stated that, "The criticism of [Joyce Gilchrist] around here is second only to that of Timothy McVeigh." After her dismissal, Gilchrist filed a lawsuit seeking $20.1 million, claiming that her firing was actually motivated by revenge, after she reported sexual misconduct by her supervisor.
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- New York Times Police Chemist Is Rebutted After Man's Execution
- New York Times In Rape Case Gone Awry, New Suspect
- New York Times Court Overturns Death Sentence
- New York Times Oklahoma Will Study Capital Cases
- New York Times Death Penalty Cases Reviewed
- New York Times Man Is Reunited with Family
- New York Times Oklahoma Governor Weighs Independent Inquiry on Lab
- New York Times Flaws in Chemist's Findings Free Man at Center of Inquiry
- New York Times Capital Case Re-Examined