JACKSONVILLE, Fla. -- Hundreds of DUI cases across the state are being called into question after an investigation into one of Florida's most prominent experts is investigated.

For the past 6 months, the Florida Department of Law Enforcement has conducted an internal investigation into Laura Barfield, an expert who would testify about breathalyzer results at DUI trials.

But the results have just been made public and one First Coast DUI attorney said that's not fair to his clients.

"As a witness, any time you come in to court and testify about something, your credibility is automatically at issue," said Attorney Lee Lockett.

Locket has met Barfield in court many times.

As an attorney specializing in DUI cases, Lockett said the FDLE internal investigation into her professional conduct is troubling.

The report, released Friday, found Barfield used her state credit card for personal purchases 57 times, including $2,700 dollars in Carnival Cruise tickets, and $3,800 dollars for shopping sprees.

"If she's willing to be careless with the truth about that, that would then beg the question, how credible was her testimony in court regarding DUIs," he said.

Lockett said they should have pulled her off the job when the investigation began in 2012.

An FDLE spokesperson told First Coast News:

Laura Barfield's resignation has nothing to do with her knowledge of the Intoxilyzer or the operations of the alcohol breath testing program. We understand the job of defense attorneys is to cause doubt, but we have confidence in our program, which has previously withstood numerous defense attorney challenges in court.

But Lockett disagrees.

"The opposing attorney will always have the option to impeach a witness and raise credibility issues. Had those attorneys known that, and had that information, many people might not be in the situation they're in," he said.

Barfield has resigned effective May 24th, but will be on a leave of absence until then.

FDLE said she could be called to testify again while she's on leave.