Dallas County District Attorney Craig Watkins filed court papers late Thursday asking a judge to halt the county's civil investigation into the employment practices of two constables.

Watkins argued in his request for a restraining order and injunction that county commissioners and their special investigator are exceeding their authority by conducting a criminal investigation of the offices of constables Derick Evans and Jaime Cortes, of Precincts 1 and 5.

Watkins said in the petition that only his office can investigate criminal matters and that investigator Danny Defenbaugh is hindering an investigation his office is conducting.

Defenbaugh, a former FBI agent hired by the county in September, is investigating the constables for abuse of office and official oppression, which are criminal violations, according to the petition.

As evidence, the petition cites sealed grand jury testimony Defenbaugh gave to the grand jury in early October after receiving a subpoena.

Watkins' petition also says there is a risk that Defenbaugh's report could become public and harm the DA's investigation.

Watkins also argued that Foster's order to seize computer data from Cortes in a pre-dawn operation, which commissioners Maurine Dickey and Kenneth Mayfield voted to ratify, was illegal.

Foster questioned Watkins' motives in seeking to halt the county probe.

"I just see a lot of conflicts of interest here," Foster said. "With all these roadblocks, it sounds to me like someone is trying to cover something up."

Foster, Dickey, Mayfield and Defenbaugh are all listed as defendants in Watkins' petition. In that sense, it's very similar to legal action taken a few weeks ago by Cortes.

Cortes is seeking a restraining order and damages against the same parties, saying their actions were illegal. A hearing is scheduled later this month.

Watkins' petition will have to be heard by an outside judge since District Judge Martin Hoffman recused himself. Most likely, retired Judge Richard Davis, who is hearing Cortes' action, will also be assigned to the Watkins case, county officials said.

Watkins could not be reached Thursday for comment.

Mayfield said Defenbaugh is not conducting a criminal investigation, and he questioned Watkins' motives in filing the petition.

"Once again the district attorney doesn't know what he's talking about," Mayfield said. "There's something he doesn't want uncovered."

Mayfield said that whenever Defenbaugh has found evidence of crimes he has turned it over to the proper authorities, including the DA.

"It may be that the DA doesn't want that. The question is, why?" Mayfield said.

In a status report Defenbaugh wrote to Foster that is attached to Watkins' petition, Defenbaugh wrote that he is trying not to interfere in any investigation the district attorney may be conducting. He said in the report that of the 52 people he's interviewed, only two have had contact with the district attorney and only one of them gave a statement.

Defenbaugh also wrote in the report that he turned over to law enforcement three allegations of crimes committed by the constables or their employees.

He also wrote that he is periodically giving information from his investigation to the DA's public integrity unit.