FBI agents confronted former Representative Eric Swalwell at San Francisco International Airport last weekend, served him with a search warrant, and seized his cellphone and other electronic devices as part of a federal criminal investigation.

Swalwell, 45, cooperated with agents during the Saturday encounter after arriving at the airport. Federal agents also executed additional court-approved warrants Sunday at his Washington, D.C., residence and seized other potential evidence. Neither the FBI nor the Justice Department has commented on the reported searches.

The investigation stems from accusations of sexual misconduct by at least four women. A former staffer has alleged that Swalwell raped her on two occasions when she was too intoxicated to consent. Another woman has accused him of drugging and sexually assaulting her in 2018. Two additional women have alleged he sent them unsolicited explicit images. Swalwell has vehemently denied the allegations, which have not been proven in court, and maintains his innocence. The Justice Department opened its investigation in April.

The accusations prompted Swalwell to end his campaign for California governor and resign from Congress in April while facing a House Ethics Committee investigation. He had served seven terms in the House, briefly sought the 2020 Democratic presidential nomination, and been a frequent critic of President Trump.

The reported FBI action also comes amid renewed scrutiny of Swalwell’s past relationship with Christine Fang, a suspected Chinese intelligence operative known as “Fang Fang.” Newly declassified records state that Swalwell told the FBI he had “occasionally hooked up” with her. Fang had cultivated ties with rising California politicians and helped bundle donations for his 2014 reelection campaign. Swalwell has not been accused by law enforcement of wrongdoing related to Fang.