"I'm just afraid of him," said the ex-employee. "He's not a nice guy all the time. On some things about Terry, I'm a fan. But all investigators can be aggressive. That's why people hire us. So I'm just nervous about that."
Mr. Lenzner, who served as assistant chief counsel for the Senate Watergate Committee from 1973 to 1975, founded IGI in 1984. With offices in London, Frankfurt, Germany, and five major cities in the United States, the Washington-based firm is now among the most sophisticated private-investigation companies in the world, Mr. Lenzner told Senate lawyers last year.
"That's one of the selling points of the firm," Mr. Shapiro said. "And he's not just any lawyer. He's a Harvard-educated lawyer with a background of being a federal prosecutor in the Southern District of New York, which many --not just its alumni -- consider the pre-eminent office in the country.
In early 1996, for example, he did not respond to many phone calls and e-mail messages from one of his employees, Susan Swanson, the first investigator to obtain evidence that the Unabomber was a hitherto unknown hermit named Theodore Kaczynski.
A skeptical IGI President Raymond W. Kelly reluctantly agreed to review Miss Swanson's evidence. But by the time Mr. Kelly responded, Miss Swanson had resorted to turning over the case to an outside lawyer. IGI had missed out on the Unabomber case.
IGI's proposal to dig up dirt on Sen. Don Nickles and his wife resulted in an angry confrontation when Mr. Lenzner appeared before the Senate Governmental Affairs Committee.
"I don't mind you messing with me," the Oklahoma Republican told him. "But I sure mind you messing with my family."
Mr. Lenzner's proposal was designed to help Cheyenne-Arapaho Indians reclaim tribal lands from the Interior Department.