JOIE CHEN, CNN ANCHOR: In Oklahoma, local, state and federal authorities are investigating Oklahoma City police forensic expert and thousands of cases in which she worked. Several of those cases ended in executions, and others have been -- have put defendants on death row. The police veteran's credibility is now in question. We turn to CNN national correspondent Bob Franken who is in Oklahoma City for more details on this still developing story -- Bob.</s>BOB FRANKEN, CNN NATIONAL CORRESPONDENT: And the reason for that, Joie, is that there is now an FBI report questioning whether this forensic scientist has, in fact, given misleading testimony, not relying on the scientific basis. It's one of several reports that have been critical of Joyce Gilchrist, a 21-year veteran of the Oklahoma City police department, who has testified, as you said, in thousands of cases. She has been criticized before, as far back as 1987 by a professional group, the same type of criticism. She is somebody who's of course associated with the police lab here. The latest critical memorandum was something that was disclosed by the local media this morning. It was written in January by a police captain, her supervisor, who said that she has mismanaged the police lab, and perhaps has called into question the evidence in several cases. She has testified in those thousands of cases. Ten of them have resulted in executions, 13 others wait on death row, including Marilyn Plantz, who is scheduled to be executed this evening. However, in this particular case, Marilyn Plantz, who was accused of a murder in 1988, has confessed to the murder and is not expected that her -- that there's going to be any kind of clemency, because there's actually no reason, says the Governor Frank Keating, to provide clemency since there is a confession. Keating says that there must be a case-by-case investigation of all those in which Joyce Gilchrist is involved. Officials say that that could literally take a period of years -- Joie.</s>CHEN: CNN national correspondent Bob Franken for us in Oklahoma City today.
Authorities Investigate Oklahoma City Forensic Expert