The D.C. Court of Appeals got a taste of mystery recently with the strange case of Bethesda attorney Barry Nace.

In 1983, Nace won a $750,000 jury verdict against manufacturers of the morning sickness drug Bendectin. Judge Joseph M. Hannon set the verdict aside, and five months later Nace got a letter from D.C. Bar counsel Thomas Henderson saying that Nace was under investigation for allegedly hiring a detective to investigate Hannon.

The plot thickened when Nace found attached to Henderson's letter a copy of Hannon's ruling in the case, stamped: "Received Sept. 8, 1983 . . . Thompson, Larson."

"There is only one law firm in the District of Columbia that fits that description," Nace has told the appeals court. "That law firm is clearly the law firm of Thompson, Larson, McGrail, O'Donnell and Hardin."

A member of that firm is John Jude O'Donnell, a longtime friend of Judge Hannon who happened to be on a committee presiding over the bar counsel budget, Nace told the court.

Just 12 days after Henderson docketed the complaint against Nace, the investigation was closed for lack of evidence. But Nace persisted in knowing who the "informants" were, and Henderson -- for the first time in the bar counsel's history -- insisted that the information was confidential, leading to a confrontation in front of the appeals court where Nace has asked that the names be revealed. Hannon declined to comment; O'Donnell said he was not involved. The judges on the appeals panel -- Theodore R. Newman Jr., John A. Terry and Chief Judge William C. Pryor -- gave no indication whether they will unlock the secret or when.

"What I really want to know is why this was done to me and who did it," Nace said. "I really want to know the connections between all of these people."