Georgia Secretary of State Brad Raffensperger's office has opened an investigation into former President Donald Trump's Jan. 2 phone call urging Raffensperger to overturn the state's election results.

"All I want to do is this: I just want to find 11,780 votes, which is one more than we have. Because we won the state," Trump told Raffensperger in the phone call, which is expected to play a prominent role in Trump's impeachment trial this week.

Raffensperger's office confirmed that it had opened the inquiry after it received a complaint about Trump's conduct.

"The secretary of state's office investigates complaints it receives. The investigations are fact-finding and administrative in nature. Any further legal efforts will be left to the attorney general," said Walter Jones, a spokesman for Raffensperger's office.

The state attorney general's office did not immediately respond to a request for comment Monday night.

After the investigation is completed, the investigators will make their findings available to the State Election Board, which is made up of two Republicans and two Democrats and is chaired by Raffensperger. The board could decide to dismiss the case, send a reprimand or refer the case to prosecutors.

In a statement last month, Fulton County District Attorney Fani Willis described the call as "disturbing" and left the door open for an investigation.

"Anyone who commits a felony violation of Georgia law in my jurisdiction will be held accountable. Once the investigation is complete, this matter, like all matters, will be handled by our office based on the facts and the law," Willis said then.

Legal experts have said the call might have violated federal and state election laws but that it would be a difficult case to prosecute.

Raffensperger, a Republican, drew Trump's fury by pushing back against claims of widespread voter fraud in Georgia in the weeks after the election. A transcript of the call was released after Trump tweeted that he had spoken to Raffensperger and that Raffensperger was "unwilling, or unable" to answer his already debunked voter fraud questions.

Trump crowed about the call at his Jan. 6 rally before his supporters' deadly riot at the U.S. Capitol.

"In Georgia, your secretary of state, who — I can't believe this guy is a Republican. He loves recording telephone conversations. You know, that was a — I thought it was a great conversation, personally. So did a lot of other — people love that conversation because it says what's going on," Trump said then. "These people are crooked."