Democrats may have the opportunity to pick up two Senate seats in North Carolina, as Sen. Richard Burr faces an investigation into his stock trades before the coronavirus pandemic and Sen. Thom Tillis faces a tight reelection battle.

On Wednesday, the FBI seized Burr's phone, as he faces a joint probe from the Justice Department and the Securities and Exchange Commission. Burr, the chairman of the Senate Intelligence Committee, has been accused of insider trading after he sold up to $1.7 million in stocks in February following a closed-door briefing about the impact of the coronavirus on the U.S. economy.

Burr has denied wrongdoing but has temporarily given up his chairmanship. If Burr is found guilty of criminal charges, it could force him to resign from the Senate, providing an opportunity for Democrats to regain his seat.

Should Burr resign before Sept. 4, a special election would be held in November.

North Carolina Gov. Roy Cooper is a Democrat. If Burr resigns after Sept. 4, Cooper would appoint one of three people put forward by the state Republicans.

In 2016, Burr beat Democratic challenger Deborah K. Ross, 51.1% to 45.4%.

Burr plans to not seek reelection for a fourth term in 2022.

North Carolina’s other senator, Thom Tillis, faces a tough reelection battle in November. Tillis’ challenger, Army veteran and businessman Cal Cunningham, outraised Tillis by more than $2 million in the first quarter of the year. A recent poll from East Carolina University shows Tillis leading Cunningham, 41% to 40%.

Tillis, who is seeking his second term, edged Democratic incumbent Kay Hagan in 2014, 48.8% to 47.3%.

Cunningham defeated four Democrats to win the nomination: Erica D. Smith, Steve Swenson, Trevor M. Fuller and Atul Goel. Only Smith posed a serious threat to Cunningham. It is unclear if any of the aforementioned candidates would consider running for the Democratic nomination should a special election be held in November.

North Carolina is considered an important 2020 battleground state. A recent poll shows President Trump leading Joe Biden, 46% to 43%.