The investigation by the House ethics committee into Representative Eric Swalwell, a California Democrat facing allegations of ties to a Chinese spy, has reached an anticlimactic end, raising questions about what the committee found.

In a letter dated May 22, the House Committee on Ethics informed Mr. Swalwell that it “will take no further action” and that he and other members should “be conscious of the possibility that foreign governments may attempt to secure improper influence through gifts and other interactions.”

The investigation followed a 2020 Axios report that found that a Chinese national, Christine Fang, had developed relationships — including sexual relationships with at least two Midwestern mayors — while targeting up-and-coming politicians in America.

Mr. Swalwell ended up being the highest-profile target of Ms. Fang’s operation. Ms. Fang was involved in Mr. Swalwell’s 2014 re-election campaign, helping to place at least one intern at Mr. Swalwell’s office and meeting him a few times.

In a statement in response to the end of the investigation, Mr. Swalwell said: “It’s time to move on,” adding, “I was nothing but helpful and never accused of wrongdoing.”

“Nearly ten years ago I assisted the FBI in their counterintelligence investigation of a campaign volunteer,” Mr. Swalwell said. “The bipartisan House Ethics Committee had this case for over two years. They had the power of subpoena. They received answers from me in response to requests for information. Today they are closing this matter and did not make a finding of any wrongdoing.”

Although Mr. Swalwell has not been accused of any wrongdoing in the events of 2014 and has not been accused of maintaining a sexual relationship with Ms. Fang, some conservatives have insisted that he did as recently as April.

Representative Marjorie Taylor Green, for one, accused Mr. Swalwell of having had a “sexual relationship with a Chinese spy,” during an exchange earlier this year on the House floor.

Speaker McCarthy removed Mr. Swalwell from his position on the House Intelligence Committee at the beginning of 2023. In Mr. Swalwell’s case it’s unclear whether it was because of the investigation or his role in impeaching President Trump.

Mr. Swalwell was the impeachment manager during the second impeachment of Mr. Trump. Representative Adam Schiff, who Mr. McCarthy also ousted from the Intelligence Committee earlier this year, was the lead prosecutor during the first impeachment of Mr. Trump.

Two other Republican speakers, John Boehner and Paul Ryan, kept Mr. Swalwell on the committee even after details about Ms. Fang’s operation were known. Mr. Swalwell said: “Neither Speaker questioned my actions nor politicized my cooperation.”

The ethics committee did not immediately respond to a request for comment.