Former city councilman Gordon Quan was mayor pro tem from January of 2002 until the end of 2003, serving alongside then mayor Lee Brown. He says his office was an open book.
"I know when I took over one of the first things we did was ask the controller's office to do an audit of our procedures to make that sure we had tight controls over all the funds in the office. I thought it was my role to establish the credibility of that office and the need to continue having a pro tem's office and what value it brought to council."
Part of the district attorneys investigation includes the possibility that the mayor pro tems office has in the past been used to fund expenditures that council members didn't want to show up as money spent by their offices. Quan says that wasn't the case while he was mayor pro tem.
"There was no piggy bank for council members. There was barely enough to pay our own expenses. We returned $50,000 to the city budget to try to show our stewardship of city funds. If the funds were not needed to operate the office they were returned to help other departments."
Quan, who's a local immigration attorney, says he welcomes the DA's investigation.
"I think there's certainly doubt that has been cast on the operations of the pro tem's office and possibily council in general. I feel like it's a doctor's check-up and let the DA come in and check it out and I hope there's a clean bill of health and if there's any problems that they be addressed directly."
Harris County District Attorney Chuck Rosenthal says he has no specific information about wrongdoing, but uses the hypothetical example of car rentals to explain how expenditures may have been hidden using the mayor pro tem's budget.
"Obviously if someone needed to rent a car for city business, that would be a perfectly understandable expense and would be approved, I'm sure, without any problem. But there may have been restrictions on what they could use out of their own budget. I've heard these allegations but I don't know whether they're criminal or not and we won't know until we see them."
Rosenthal's investigative powers include only the Brown and White administrations. He says he has no idea how long the investigation will take.