Ahead of the hearing scheduled next week over Mark Meadows' effort to move the Fulton County RICO case to federal court, Fulton County District Attorney Fani Willis has now issued multiple subpoenas for witnesses to appear, according to court filings in the case.

A federal judge last week ordered an "evidentiary hearing" on Meadows' motion to remove the case to federal court. Now, four witnesses are subpoenaed to appear.

Willis filed subpoenas on Thursday that had been issued for Secretary of State Brad Raffensperger and investigator Francis Watson -- both of whom Trump called in the wake of the 2020 election as part of his alleged effort to overturn the results.

Earlier this week, Willis also filed subpoenas for Kurt Hilbert and Alex Kaufman -- both of whom were on the Trump-Raffensperger call, according to a transcript of the call.

The subpoenas instruct the witnesses to appear in court for the Meadows hearing on Monday, according to copies of the subpoenas included in the court filings.

That hearing is set for Aug. 28 at 10 a.m. in Atlanta.

The same day Donald Trump is expected to surrender at Fulton County Jail, House Judiciary Chairman Jim Jordan, R-Ohio, launched a probe into whether District Attorney Fani Willis coordinated with federal officials, including special counsel Jack Smith.

In a new letter, Jordan demands information and communications with the Department of Justice and federal officials on the funding Willis' office receives.

"Ms. Willis's indictment and prosecution implicate substantial federal interests, and the circumstances surrounding her actions raise serious concerns about whether such actions are politically motivated," the release states.

Willis rejected any claims of the indictments being politically motivated in a recent radio interview.

"There's really nothing sexy about this," Willis told Atlanta Up Close's Maria Boynton. "There's allegations of a crime and then to look at the law and if the facts bear out that the law has been broken, then we have a duty and a responsibility to bring charges."

-ABC News' Lauren Peller and Peter Charalambous

Former President Donald Trump is expected to shake up his legal team as soon as Thursday, just hours ahead of plans for Trump to surrender to authorities in Fulton County, Georgia, sources with direct knowledge tell ABC News.

Drew Findling is expected to depart the team and be replaced by attorney Steven Sadow, according to the sources.

Read more about the decision.

Former President Donald Trump is expected to surrender to authorities in Georgia on Thursday.

A judge had set his bond at $200,000 on Tuesday.

Trump and 18 others were charged last week by Fulton County District Attorney Fani Willis in a sweeping racketeering indictment for alleged efforts to overturn the results of the 2020 presidential election in the state of Georgia.

The former president says his actions were not illegal and that the investigation is politically motivated.

-ABC News’ Olivia Rubin, Will Steakin and Peter Charalambous