Karen Friedman Agnifilo, right, of the Manhattan district attorney's office, recused herself from the case.
Marc A. Agnifilo was at his weekend home in upstate New York near the Berkshires, watching his three children after dinner on a Saturday evening when his cellphone rang.
His law partner, Benjamin Brafman, told Mr. Agnifilo that Dominique Strauss-Kahn, who had just been arrested in Manhattan on charges of sexual assault, had retained their law firm.
And with that phone call, the balance of a complicated, two-lawyer household would be upset yet again: His wife, Karen Friedman Agnifilo, is the chief of the trial division in the Manhattan district attorney’s office, which would be prosecuting the case.
Since her husband’s firm was representing Mr. Strauss-Kahn, Ms. Friedman Agnifilo would have to recuse herself.
“Oh, I’ll call Cy right now,” Mr. Agnifilo said his wife told him, referring to Cyrus R. Vance Jr., the Manhattan district attorney.
In the nearly 18 months since Mr. Vance took office, the Agnifilos have been in this situation some two dozen times, creating the potential for awkward situations at work and home. But the Strauss-Kahn case, the biggest in Mr. Vance’s tenure, puts extra scrutiny on their positions.
Ms. Friedman Agnifilo, as head of six trial bureaus and nine other specialty units in the district attorney’s office, is typically the supervisor of major cases, including murders, rapes, assaults and robberies.
Her absence from this case would seem to be an especially tough loss for the district attorney’s team because Ms. Friedman Agnifilo used to be the deputy chief of the office’s sex crimes unit. Mr. Strauss-Kahn is charged with sexually assaulting a hotel housekeeper.
But a spokeswoman for Mr. Vance said that the office was equipped to handle the absence of any of its top assistants.
“The senior staff is a really strong team,” said Erin M. Duggan, Mr. Vance’s chief spokeswoman.
If a senior assistant has to recuse herself, Ms. Duggan added, “there are plenty of others who can fill in.” In this case, John Irwin, the deputy chief of the trial division, is supervising the Strauss-Kahn case in Ms. Friedman Agnifilo’s place.
Staff members recuse themselves from cases in which they have significant professional or personal associations, Ms. Duggan said.
“It’s really done with an abundance of caution just to avoid even the appearance of a conflict,” she said.
Assistants who recuse themselves from cases are walled off from any briefings, memos or any other internal information or dealings with the case.
Mr. Agnifilo said that he had not even been aware of Mr. Strauss-Kahn’s arrest until Mr. Brafman called him. Since then, he said, the only discussion he has had with his wife about the case concerned “the raw volume of the press” coverage.
He said that he and his wife, who declined to comment for this article, had become accustomed to keeping information about certain cases from each other. Mr. Agnifilo said that his former job as a federal prosecutor in New Jersey prepared him for withholding certain information from his wife. In some cases, Mr. Agnifilo said, he had top secret clearance.
He recalled being asked by one of the top assistants in the United States attorney’s office, “Are you comfortable not telling anyone about what you learn, including your wife?”
“It’s never been awkward,” Mr. Agnifilo said. “We’re pretty regimented about it. If she’s recused from a case, we really don’t talk about it.”
There were times when he wished he could have talked to his wife about some of his big cases, Mr. Agnifilo said. Yet over time, they have adjusted and, in general, do not talk about work as much, he said.
The couple, who married in 1996, met while working in the district attorney’s office in 1992. Ms. Friedman Agnifilo had just been hired, Mr. Agnifilo said, and she assisted him on a case in which two deliverymen for the Dizzy Izzy Bagel Store got into an argument over a parking spot that ended with one cutting off the other’s arm with a machete. Mr. Agnifilo is now a partner at Brafman & Associates, where Mr. Brafman, the high-powered defense lawyer, is one of Mr. Strauss-Kahn’s lead lawyers, along with William W. Taylor III of Washington.
It was Ms. Friedman Agnifilo who introduced her husband to Mr. Brafman, during a district attorney alumni event in January 2006. She told Mr. Brafman: “My husband is the best trial lawyer in America. You should meet him.”
“That’s not possible,” Mr. Agnifilo recalled Mr. Brafman saying, “because I’m the best trial lawyer in America.”
Although Ms. Friedman Agnifilo distances herself from cases in which her husband or his law firm is involved, the fact remains that all the assistant district attorneys prosecuting opposite Mr. Agnifilo work for Ms. Friedman Agnifilo.
Ms. Duggan said that in the close-knit legal world, many defense lawyers have professional and personal relationships with prosecutors in the office. Many defense lawyers also used to work in the office, Ms. Duggan said.
“Nobody would believe they would be anything less than 100 percent aggressive,” she said.
Mr. Agnifilo said he would never bring complaints about a prosecutor to his wife.
“If I had a really tough day and I feel like someone’s being unreasonable, I don’t mention it,” he said.