Eric Swanson received a startling call last Thursday from his wife, Shana Madoff, who said that something was terribly wrong.

Officials from the Securities and Exchange Commission and the Justice Department had swooped down on the offices of Madoff Investment Securities, where Shana Madoff was the compliance lawyer, seizing records and asking pointed questions as they began investigating one of the largest frauds in Wall Street history.

Swanson, who only a year earlier had married into the Madoff family, had an intimate familiarity with the SEC. For 10 years he had been a midlevel official at the commission’s Washington headquarters. He had also occasionally worked on matters involving the Madoff firm in the years before he became romantically involved with Madoff in 2006, just as he was preparing to leave the SEC. Shana Madoff is the niece of Bernard Madoff, the central figure in the scandal, and the daughter of Peter Madoff, who was the firm’s chief compliance officer.

As the investigation unfolds, Swanson finds himself in the unique position of having roots in the family at the center of the scandal and older ties to the government regulator that failed to uncover the scheme. As both come under closer scrutiny for the events that have led up to the loss of billions of dollars, Swanson has been attacked in blogs and some news accounts that have suggested his relationship with the Madoffs was a central reason that the commission turned a blind eye to the Ponzi scheme.

Eric Starkman, a spokesman for Swanson, said Swanson would fully cooperate with such a review. But in fact, the work Swanson did that touched on the Madoff firm was relatively minor, and no evidence has emerged that Swanson did anything involving the firm after he became close to Shana Madoff in the spring of 2006, current and former commission officials with knowledge of his work said in recent interviews.

Swanson has told friends that he met Shana Madoff in October 2003 when she served on a compliance committee of an industry group. In April 2006, they became romantically involved while he was visiting New York. On Dec. 8, her birthday, he proposed to her.

The scandal has taken more than a personal toll on Swanson and his wife. Shana Madoff has told friends that she has lost a substantial portion of her assets, which she invested with her uncle.