The Texas attorney general, Ken Paxton, is set to be deposed Thursday over allegations that were central to his impeachment last year, with the upcoming proceedings being the first time he’ll be required to sit for questioning under oath.

Last week, a judge at Travis County denied an attempt by Mr. Paxton to end the case in question, alleging wrongful termination, without him sitting for questioning under oath.

Four of Mr. Paxton’s former top aides are alleging that they were punished for alerting the FBI of their suspicions that Mr. Paxton was engaged in a bribery scheme.

The allegations stem from a relationship between Mr. Paxton and a political donor, Nate Paul, a real estate mogul. Mr. Paxton was acquitted by the Texas senate in impeachment proceedings last year, though he is still facing both state and federal securities fraud cases.

The former aides to Mr. Paxton are now claiming that Mr. Paxton’s decision to fire them, which they say is because of their decision to tip off federal investigators, is in violation of the Texas Whistleblower Act.

In a statement released Friday, Mr. Paxton’s office called the order to have him sit under oath “unnecessary” and “lawless,” and said it would ask the Texas Third Court of Appeals to “put a stop” to the order.

Mr. Paxton’s office has asked that court to block his deposition and close the case before — unsuccessfully. The Texas supreme court also sided with the appeals court in backing the county court’s decision to force him to testify.

Still, Mr. Paxton’s office said it would accept any outcome in the case and would no longer contest the facts, saying it prefers “to focus on the critical challenges facing our State, including the unprecedented flood of illegal immigration at our southern border.”

An attorney for one of the whistleblowers, TJ Turner, told KXAN, “I think the last thing Ken Paxton wants to do is put a hand on his Bible and tell the truth, and he’s going to avoid that at all costs,” adding, “I think there will be another legal maneuver, and we’ll wait and see what that is.”

If and when Mr. Paxton is deposed on Thursday, it could have implications for the other criminal cases against him. The scheduled deposition also comes at a time when the embattled attorney general has taken on a national profile for his face-off against the federal government over federal border patrol’s attempts to access the southern border.

Federal law enforcement has been attempting for months to access a section of the border that Texas law enforcement has blocked with razor wire. Although the Supreme Court ruled that federal law enforcement may remove the wire to access the area, Mr. Paxton has been defiant, writing in a letter to the Department of Homeland Security, “Your request is hereby denied.”

“As I said before, this office will continue to defend Texas’s efforts to protect its southern border against every effort by the Biden  administration to undermine the State’s constitutional right of self-defense,” Mr. Paxton wrote.