The Georgia prosecutor investigating the conduct of former President Donald Trump and his allies after the 2020 election is trying to compel U.S. Sen. Lindsey Graham and former New York Mayor Rudy Giuliani to testify before a special grand jury.

Fulton County District Attorney Fani Willis on Tuesday filed petitions with the judge overseeing the special grand jury. Fulton County Superior Court Judge Robert McBurney signed a “certificate of material witness” for Graham, Giuliani and others saying that they have been deemed necessary to the investigation. Representatives for Giuliani and Graham did not immediately respond to requests for comment.

Trump was the first Republican since 1992 to lose the state in a presidential election. Following his election loss, a tape surfaced of Trump's conversation with Georgia Secretary of State Brad Raffensperger asking him to “find” enough votes for him to flip the election.

Raffensperger refused despite an aggressive pressure campaign.

Trump alleged election fraud in court, but his legal challenges failed to gain traction.