Last week’s disclosure by Ronald C. Machen Jr., the United States attorney for the District of Columbia, that his office had secretly seized telephone records of Associated Press reporters as part of a leak investigation surprised and shocked many people.

But to some on Wall Street, Mr. Machen’s involvement in a phone records case had a familiar ring. They recalled the case of Allied Capital, a formerly high-flying business development company based in Washington whose shares collapsed in 2009. Two years earlier, Allied had admitted that one of its investigators had stolen the phone records of a prominent hedge fund manager who had been critical of the company’s accounting practices. The chief outside lawyer counseling Allied was Mr. Machen, then a partner at WilmerHale.

Mr. Machen, whose office is investigating the leak of national security information to the media, sent a letter May 10 to The Associated Press disclosing that it had collected two months of reporter phone logs without notifying the company in advance, as is typical. The phone record seizure was unusual and although it was unclear what the government wanted from the records, it appeared to be part of a Justice Department investigation into a news leak involving a Yemeni terrorist plot.

Eight years ago, Mr. Machen was on the other side of an investigation involving the seizure of phone logs. His client, Allied Capital, had been linked to the theft in 2004 and 2005 of phone records belonging to David Einhorn, founder of Greenlight Capital, a major hedge fund. At the same time that Mr. Einhorn’s records were stolen, so were the phone logs of a business reporter and a research analyst. All three had publicly criticized Allied’s accounting and business practices.