In an incredibly rare move this week, the foreperson of a Harris County Grand Jury asked a bailiff to remove prosecutors so jurors could hear from a witness on their own about potentially faulty DWI tests.
13 Undercover first raised questions about the accuracy of the Houston Police Department's so-called BAT vans, but now it's the investigation into how those problems were handled that's causing controversy.
For months, some of the people closest to HPD's breath testing vans have told you and us that the vans are unreliable -- meaning the roadside tests they do on alleged drunk drivers may not be accurate.
Now the controversy has spilled over into a grand jury investigation, and it's become so heated that a prosecutor working for Harris Co. District Attorney Pat Lykos was thrown out of the grand jury room earlier this week under the threat of arrest.
Amanda Culbertson worked for HPD for four and a half years as one of the supervisors overseeing mobile breathalyzer machines known as the BAT vans. She quit when she says HPD's poor maintenance was leading to unreliable test results.
But her real trouble started when she spoke out about it. After Culbertson told a judge about her concerns, the DA questioned her credibility and pushed the county to cancel a contract with her new employer, in essence firing her.
Culbertson told her lawyer Chip Lewis that the DA is targeting her.
"She has not only thought it herself, but been told by people very close to the fire that the District Attorney's Office is after you," said Lewis.
This week a Harris County Grand Jury wanted to hear from Culbertson as well as Brent Mayr, a former prosecutor who previously alleged the DA is bullying Culbertson to force her silence.
"Clearly retaliation for these individuals expressing opinions that the DA's office didn't like," Mayr said on October 4.
When Mayr walked in to testify before the grand jury on Tuesday, the foreperson told prosecutors to get out. They wanted to hear from Mayr and Culbertson without a DA in the room.
"They obviously believe that the DA's Office played a role in this case and that they can't be independent," said KTRK Legal Analyst Joel Androphy.
While it is rare -- and legal -- the DA's Office threw a fit. Court records show top assistants to the elected DA refused to leave the room until a bailiff threatened to arrest them. The DA tried to force a judge to let them back in, but it was denied. An appeals court said the same thing.
"The grand jury is a function of independent people from the community. It's not supposed to be the vote of the DA's office," said . "This is rare and it would happen one out of a hundred times that a grand jury would have the courage enough to basically say to the DA's Office get out of here or you're going to get arrested."
We tried to ask the DA about it Friday, but they refused repeated interview requests. We'd love to ask what they knew about the BAT van problems, when, and what they did about it. It may be the same thing the grand jury is looking at on its own; and it may be the reason the DA was so angry about being thrown out of a supposed independent investigation.
"It's clear to me that the grand jury has questions about how this was handled from a law enforcement standpoint. Now, I don't know if that's specifically confined to how HPD treated her or if they have some beef with what the District Attorney's Office did as well," said Lewis.
Androphy told us in cases like this it would be best for the DA to ask for an independent prosecutor, but the DA's Office said they haven't. It would've been one of the questions we asked if anyone at the DA's Office would've been willing to join us for an interview, but no one was.
13 Undercover and Wayne Dolcefino exposed the potential maintenance problems with the BAT vans back in March. We found documents detailing electrical problems that kept some of the very expensive mobile breath vans from ever being used. We showed you emails showing some cops were worried it might affect criminal cases. HPD didn't tell the DA's Office.
"It's not that we are trying to hide it, but I don't see a need in telling them that; if they want to know that, we'd be glad to share that information with them," said Captain Carl Driskell with HPD.
When we asked if the DA's Office ever asked for the information, Capt. Driskell replied, "No."
Stay tuned to Eyewitness News for continuing coverage of the BAT van investigation.