Editing West Memphis Three (section)

===John Mark Byers' knife (1993)===
John Mark Byers, the adoptive father of victim Christopher Byers, gave a knife to cameraman Doug Cooper, who was working with documentary makers [[Joe Berlinger]] and Bruce Sinofsky while filming the first ''[[Paradise Lost: The Child Murders at Robin Hood Hills|Paradise Lost]]'' feature. The knife was a folding [[hunting knife]] manufactured by [[Kershaw Knives|Kershaw]]. According to the statements given by Berlinger and Sinofsky, Cooper informed them of his receipt of the knife on December 19, 1993. After the documentary crew returned to New York, Berlinger and Sinofsky were reported to have discovered what appeared to be blood on the knife. HBO executives ordered them to return the knife to the West Memphis Police Department. The knife was not received at the West Memphis Police Department until January 8, 1994.

Byers initially claimed the knife had never been used. However, after blood was found on the knife, Byers stated that he had used it only once, to cut deer meat. When told the blood matched both his and Chris' blood type, Byers said he had no idea how that blood might have gotten on the knife. During interrogation, West Memphis police suggested to Byers that he might have left the knife out accidentally, and Byers agreed with this.<ref name="Leveritt03" /> Byers later stated that he may have cut his thumb. Further testing of the knife produced inconclusive results about the source of the blood. Uncertainty remained due to the small amount of blood<ref name="Leveritt03" /> and because both John Mark Byers and Chris Byers had the same [[Human leukocyte antigen|HLA]]-DQα genotype.

Byers agreed to and passed a polygraph test about the murders during the filming of ''Paradise Lost 2: Revelations'', but the documentary indicated that Byers was under the influence of several [[psychoactive drug|psychoactive prescription]] [[Pharmaceutical drug|medications]] that could have affected the test results.