The Department of Homeland Security is looking into allegations that Rep. Eric Swalwell hired a nanny who was not legally authorized to work in the U.S., U.S. Citizenship and Immigration Services said in a statement Sunday.

"USCIS has been collecting information on the allegations involving Congressman Eric Swalwell's hiring of a Brazilian national as a nanny without lawful work authorization. USCIS has referred this matter to DHS law enforcement for investigation," a USCIS spokesperson told CBS News in a statement.

Politico first reported DHS' probe into the nanny. Swawell did not immediately respond to CBS News' request for comment.

According to a report from The New York Post published Saturday, Swalwell hired a nanny for his children who then kept working for them after her work authorization permit expired in 2022. Swalwell was sponsoring her for a green card, but she allegedly continued working for him during that process even though she was not allowed to do so. A permanent labor certification was approved in 2024, according to the Post.

The DHS probe into Swalwell comes as the Manhattan District Attorney's Office says it has opened an investigation into the California gubernatorial candidate over sexual assault allegations by a former staffer.

Swalwell, who had been one of the leading contenders in the California governor's race, suspended his bid on Sunday as calls from several high-profile fellow House Democrats and other continued to grow. Rep. Anna Paulina Luna, a Florida Republican, has also announced plans to force a vote to expel Swalwell over the allegations. A vote could come as soon as midweek.

Swalwell has denied the accusations, saying in a statement they are "false and come on the eve of an election against the frontrunner for governor. For nearly 20 years, I have served the public — as a prosecutor and a congressman and have always protected women."

The allegations against Swalwell were first reported Friday by the San Francisco Chronicle, which published a story detailing a former staffer's alleged encounters with Swalwell in California and in New York.

The former staffer, who was not named in the Chronicle's story, alleged that after going out for drinks with Swalwell in September 2019, she woke up naked in his hotel bed with little recollection of the night. She also alleged Swalwell had sent her inappropriate photos of himself via Snapchat, requested nude photos of her and asked her to perform oral sex in a parking lot. 

The former staffer also claimed that in 2024, when she no longer worked for Swalwell, she met him for drinks in New York after a charity gala. She said she became intoxicated and only remembers parts of the night, including allegedly pushing him away and telling him "no" while he forced himself on her. She said she woke up the next morning with vaginal bleeding and bruises.

The Chronicle said it reviewed texts the woman sent to a friend three days after the alleged incident, in which she wrote she was "sexually assaulted" by Swalwell.