HOUSTON - An expert witness with Harris County Institute of Forensic Sciences is under fire, accused of lying on the stand.

It puts nearly 10 years of DWI cases in jeopardy.

KHOU 11 News dug up court testimony transcripts that show Dr. Fessessework Guale, a toxicology operations manager at HCIFS, claimed to have a Master's of Science degree in Toxicology from Oklahoma State University.

It turns out that's not true.

"That's a lie, she has a masters in physiological sciences," said Tyler Flood. "But when you look closer it doesn't relate to humans."

Flood is a defense attorney and President of the Harris County Criminal Lawyer's Association. He says that lie on the stand impacts 60-75 of his clients and that's just the beginning.

"There's hundreds, hundreds," said Flood.

HCIFS first employed Dr. Guale back in 2000. She's climbed up the ranks over time and started testifying in DWI and other felony cases as an expert witness for the Harris County District Attorney's office in 2006.

"She needs to be credible," said Dr. Roger Kahn, director of Harris County's Crime Lab. "She needs to be accurate, and we need to be confident her testimony is reliable."

Dr. Kahn says when his office realized Dr. Guale was misrepresenting her credentials in court, they took action and notified the DA's office.

They've since alerted defense attorney's across our area to review their cases.

"Our reputation means everything to us," said Kahn.

Right now, that reputation is questionable in court. Dr. Guale does have a Doctorate in Veterinary Medicine from Ethiopia, but her toxicology training at Oklahoma State only relates to animals.

"We see which articles she's composed," said Flood. "Articles about rectal temperatures in donkeys."

Flood says cases need to be re-opened.

"Some people may be in prison right now for many, many years because of her testimony," said Flood.

The ME's office tells KHOU 11 News it does believe she's qualified, but is committed to getting to the bottom of why she lied in court.

"It's up to us to restore the credibility of the agency, to do a complete review until the community is satisfied," said Kahn.

Dr. Guale's duties have been reassigned pending courtroom testimony re-training and the completion of the investigation.