West Virginia Senator Joe Manchin tells WDTV 5 News he isn't opposed to calling Hunter Biden as a witness in President Trump's impeachment trial.

Democrats have largely said Biden isn't relevant to the president's impeachment. Manchin, however, said if Republicans can show he has direct information related to the impeachment charges brought by the House, he would support hearing his testimony.

Senate Minority Leader Mitch McConnell, R-Ky., has left the door open to the possibility of subpoenaing the former vice president's son. Republicans want to hear about his business dealings with a Ukranian gas company.

Biden isn't the only witness Manchin said he is open to hearing from during the impeachment trial, set to begin next Tuesday.

"Anyone who has pertinent information to the charges against the president should be able to be called," Manchin said. "I don't know if he falls into that, but if it's pertinent, that's what has to be done."

Manchin said White House Chief of Staff Mick Mulvaney and former National Security Advisor John Bolton already fall into that category.

McConnell hasn't made it clear if witnesses will be called at all during the trial. Manchin said he won't reject any witness who has information that could inform his vote as a juror in the trial.

"If they can show the person is directly involved and has direct knowledge, that person should be able to be considered," Manchin said.

Chief Justice John Roberts will swear all 100 senators in as jurors Thursday. The trial is expected to begin in earnest Tuesday after the Martin Luther King Jr. holiday.

"I'm not looking forward to this at all," Manchin said. "This is an unbelievable situation we're put into. It's the most serious thing you can do as an elected official in Congress."

The West Virginia Democrat's biggest concern is the fairness of the impending trial.

"I don't know how you have a fair trial unless you're able to call witnesses and see evidence," Manchin said. "If that's not able to happen, I don't know how you're able to have a fair trial. It will be a sham of a trial.

"I want to make sure it's fair. I'm going to be fair to everybody. I'm not making a political decision. The people making statements on how they believe the president's guilty or innocent before they've seen anything, then how can you be a juror?"