FORT WORTH -- The Texas Department of Transportation is requesting that the city pay back $231,000 of a grant used to pay officers at the center of an alleged scheme to collect overtime pay.

Three police officers resigned and six were fired last year after an investigation into whether traffic tickets were altered so the officers could collect overtime pay under the Selective Traffic Enforcement Program.

"When you owe a bill, you pay a bill, and that's what we have a responsibility to do," Mayor Mike Moncrief said.

The firings resulted from a department investigation that found six officers had tampered with governmental records when they repeatedly altered times on tickets to indicate that they had been issued later.

Neglect of duty and violation of police rules were cited as cause for termination. All six appealed their firings, attorneys said.

No criminal charges have been filed, but police officials have said that the U.S. attorney's office is reviewing the results of the investigation. Police have said the officers could face felony charges ranging from falsifying a government document to fraud.

"What took place put us in a very embarrassing position, and it's behavior that's not going to be tolerated by this city, by this chief, by this council, by this mayor," Moncrief said.

The Transportation Department conducted an audit and billed the city for all the hours those officers worked over three years, said Jim Cotton, a department spokesman.

"The state is in the same condition our city is. We have very difficult budgets in front of us," Moncrief said. "They're collecting bills that are owed."

Obviously, the news was not welcome for a cash-strapped city watching every nickel.

Money to pay the state back will likely come from the city's fund balance, a reserve account used for unforeseen costs, said Horatio Porter, the city's budget director. Each department, though, also has a fund balance, so the Police Department will also likely look to identify funds to cover the bill.

The council mandates that the city's general fund balance contain 10 percent of budget expenditures. In Fort Worth's case, that's about $55 million, Porter said.

Authorization from the council is required to dip into it.

Staff writer Deanna Boyd contributed to this report.

John Henry, 817-390-7539