ProPublica reported that the FBI investigated allegations involving U.S. Sen. Susan Collins and former Navatek CEO Martin Kao, who allegedly told investigators that political donations helped the defense contractor secure federal contracts.

The report said an internal Navatek email indicated Collins had committed to helping the company obtain $32 million in naval contracts after Kao directed $150,000 through a shell company to a super PAC supporting her.

Collins’ office denied the allegations, saying the claims came from Kao, who pleaded guilty to multiple financial crimes, and that the FBI previously investigated the matter without finding wrongdoing by Collins or her campaign.

ProPublica reported that FBI agents later sought to expand the investigation into possible bribery involving members of Congress, but the effort was disrupted after agents and Justice Department officials involved in the case left the government following the return of President Donald Trump, WMTV 8 has reported.

Collins is seeking a sixth Senate term against Democratic candidate Troy Jackson, who criticized the allegations, while the White House referred questions about the report to the FBI, which said an earlier investigation found nothing implicating Collins or her campaign.