North Carolina Republican Sen. Richard Burr is stepping down from his position as intelligence committee chairman after the FBI seized his phone. 

“This morning, I informed Majority Leader McConnell that I have made the decision to step aside as Chairman of the Senate Intelligence Committee until this investigation is resolved,” Burr said in a statement on May 14. “The work the Intelligence Committee and its members do is too important to risk hindering in any way. I believe this step is necessary to allow the Committee to continue its essential work free of external distractions.”

Burr sold stocks in companies like Wyndham Hotels and Resorts according to reporting by NPR.

According to the LA Times, federal agents seized Burr’s cellphone Wednesday night as part of the Justice Department’s investigation into controversial stock trades he made as the novel coronavirus first struck the U.S.

Burr, the chairman of the Senate Intelligence Committee, turned over his phone to agents after they served the lawmaker a search warrant at his residence in the Washington area.

The seizure represents a significant escalation in the investigation into whether Burr violated a law prohibiting lawmakers from trading on insider knowledge gained from their government work such as the STOCK Act.

Burr acknowledged selling the stocks because of COVID-19 but said he relied “solely on public news reports.” He said that he utilized CNBC’s daily health and science reporting out of Asia to make his financial decisions.

While the senator denied any wrongdoing, he already announced that he does not plan to run for re-election in 2022.

Correction: A previous version of this article incorrectly stated that Sen. Richard Burr bought stocks in the company Zoom before the COVID-19 pandemic. The mistake has been corrected.