A person close to Mr. Broidy rejected the suggestion that the subpoena represented an escalation of or an expansion in the investigation of Mr. Broidy. The person said that for the past year, Mr. Broidy has been the subject of an investigation being conducted by the public integrity section of the Justice Department’s Criminal Division, using a grand jury empaneled in Washington.
The public integrity section late last year issued a subpoena to Lisa Korbatov, a Los Angeles conservative activist who worked with Mr. Broidy on his arrangement with the Angolan government, for documents related to Mr. Broidy, Circinus and other companies, according to a person familiar with the investigation.
But, highlighting the overlap between the work of different federal prosecutors, Ms. Korbatov was also named in the Brooklyn prosecutors’ subpoena of the inaugural committee. So, too, were two other Broidy associates involved in the Angola arrangement — Dolapo Asiru, a Nigeria-born California investment banker, and Nickie Lum Davis, a political fund-raiser who has retained the prominent trial lawyer Abbe D. Lowell to represent her.
Ms. Davis and Mr. Broidy have also attracted scrutiny in a related matter being handled by the Justice Department’s public integrity section — the investigation into an alleged scheme to launder millions of dollars into the country to help a flamboyant Malaysian financier known as Jho Low end a Justice Department investigation.
Another figure in that investigation, the entertainer and businessman Pras Michel, was charged in May with conspiring to funnel millions of dollars of Mr. Low’s money into the 2012 presidential election. Mr. Michel, a former member of the Fugees, a defunct hip-hop group, has pleaded not guilty. He has been asked by prosecutors for information on what Mr. Broidy did to help the financier, according to a person familiar with the investigation.
Mr. Broidy’s lawyers have said he never lobbied the Trump administration to end the investigation into the Malaysian fund.
Two other associates of Mr. Broidy’s have cooperated with prosecutors after being caught up in the investigation of the special counsel, Robert S. Mueller III, into Russian interference in the 2016 presidential election.
Rick Gates, who was paid at least $125,000 by Mr. Broidy for advice on navigating the Trump administration, pleaded guilty to conspiracy and lying to the F.B.I. And George Nader, a political adviser to the de facto ruler of the United Arab Emirates who helped Mr. Broidy’s company win contracts worth at least $200 million with the oil-rich gulf nation, cooperated with Mr. Mueller’s team before being arrested this month on child pornography charges.