Discredited Oklahoma chemist Joyce Gilchrist is back in the news. We last wrote about her here, reporting that 11 people have been executed based on her work.

The news today: the Associated Press has obtained a confidential police memo that shows:

Gilchrist doctored trial evidence and may have destroyed hair samples that could have exonerated a man now on death row....The memo said Gilchrist not only altered her own case notes, but "there is compelling circumstantial evidence" that she "either intentionally lost or destroyed" crime-scene hairs used to convict Curtis Edward McCarty of murder so the evidence could not be retested.The Oklahoma City Police Department memo, written by then-Deputy Chief Bill Citty to then-Chief M.T. Berry, is dated Sept. 21, 2001, and details 14 days of deliberations and testimony heard by a department review board.

You can read more news reports about Gilchrist in the Hall of Shame.