“The government’s inquiries into Mr. Schock’s sexuality and romantic relationships were not just distasteful and offensive,” Schock’s attorneys wrote. “They were prejudicial.”

A spokeswoman for the U.S. Attorney’s Office in the Central District of Illinois, which is prosecuting the case, declined to comment.

Schock, 36, a former Illinois congressman whose Capitol Hill office was decorated in the style of the TV show “Downton Abbey,” and whose six-pack abs landed him on the cover of Men’s Health, was charged last year with misspending government and campaign money for his personal benefit. By that time, he had resigned his position in Congress amid reports of possible misspending. His attorneys have vigorously contested the charges against him and contended that prosecutors acted over-zealously in a number of ways.

Among their assertions are that prosecutors made misleading assertions as they questioned witnesses in front of a grand jury; turned a congressional aide into an informant and had him record conversations surreptitiously in the congressman’s district office; and probed too deeply into Schock’s personal life.

“The government has investigated nearly every facet of Mr. Schock’s professional, political, and personal life,” defense attorneys wrote. “This even includes his sex life. It is no secret that there has long been speculative gossip in the media about Mr. Schock’s sexual orientation. For no apparent reason, the government has felt itself compelled to investigate this too.”

Defense attorneys highlighted several lines of inquiry that they said bore no relevance to the charges that Schock faces. They said prosecutors questioned witnesses about whether Schock slept in the same room as a then-girlfriend on a trip to Jamaica, and made skeptical inquiries about Schock’s relationship status with the woman. At one point, they said, Assistant U.S. Attorney Timothy A. Bass asked a witness if Schock and the woman were dating, and when the witness responded that it was complicated, Bass pressed for more.

“I’m just asking you if they were dating,” Bass said. “And you said they went out on dates, but you don’t know if they were dating. Now explain that to me. How do you go out on dates and not be dating?”

Defense attorneys said an informant had told investigators, incorrectly, that the woman was not thought to be Schock’s girlfriend, but instead was helping cover up his being gay. They alleged that prosecutors looked into the matter meticulously, even questioning another man the woman was romantically involved with about Schock. Schock, they said, did not know the other man, and they said even asking him for information was “astonishing and inappropriate in its own right.”

The attorneys referenced discussions between investigators and witnesses about whether Schock was gay, although it was not always clear who brought up the subject. One witness, Schock’s former chief of staff, told investigators he had “no evidence” of Schock being gay, defense attorneys alleged. A photographer who was hired by Schock told investigators he was aware of false rumors about him and the congressman, and weighed whether he wanted to be seen with Schock because of them.

Bass, the defense attorneys said, had not asked about Schock’s sexuality directly, but he did follow up.

“And the allegations that you raised that I didn’t ask you about, you affirmatively said not true; right?” Bass asked, according to a transcript in the defense attorneys’ filing.

“Yeah, it’s not true,” the photographer said.