AUSTIN — Attorney General Ken Paxton has once again failed to remove the judge presiding over his criminal case.

On Thursday morning, Paxton's attorneys were told their latest request that Judge George Gallagher be forced to step down could not be honored. Why? The court they asked does not have the authority to make this decision.

"The undersigned does not have that power," Judge Mary Murphy, presiding judge in the First Administrative Judicial Region, wrote in an email. The decision, she said, lies with "the trial court and the appellate courts."

This week, Paxton requested she remove Gallagher, whom Murphy assigned to the case in August 2015. Paxton's attorneys argued that Gallagher was on loan to the administrative court region that included Collin County when Murphy assigned him to the case and that his assignment expired in 2016. They said any decisions made this year — including a rare ruling to move the trial venue from Collin to Harris County — were therefore null and void.

In response, Murphy said she couldn't do that. She added that, as far as she understood, the case still resided in Collin County court, but no one had asked the district court judge there to weigh in. While she "has the power to terminate the assignment in question," Murphy said the Collin County judge had not asked her to do that.

This isn't the first time Paxton has tried to force Gallagher off the case. He hasn't given an explicit reason why he wants him removed, but he has taken issue with Gallagher's decision to move Paxton's upcoming trials. They're scheduled to kick off in Houston in mid-September.

Paxton was indicted in July 2015 on three felony counts of violating state securities laws. He faces two first-degree felony fraud charges over accusations that he duped investors into buying stock in a North Texas technology firm without disclosing he was receiving a commission. These charges carry a maximum penalty of 99 years in prison and tens of thousands in fines.

He also is accused of failing to register with the state while making a commission off funneling clients to a friend's investment firm, a third-degree felony.

The U.S. Securities and Exchange Commission brought related civil charges against the attorney general. A federal judge threw out these charges twice, saying the SEC did not have enough proof that a trial should be held on the merits of the case.