WASHINGTON — A former CIA officer who was arrested in May after investigators found 303 gold bars worth $40 million at his home is working to finalize a plea deal with federal prosecutors that could help keep the case shrouded in mystery.David Rush and the Justice Department have a “plea agreement in principle,” the parties said Friday, and are asking a judge to extend a forthcoming deadline for the case to be indicted.Rush had only formally been charged with one count of theft of public funds, accused of falsifying pay records in a case that was presented by criminal complaint and has not yet been presented to a federal grand jury. “The parties need additional time to prepare the paperwork, including an agreed upon statement of facts,” Assistant U.S. Attorney Raizza Ty and Rush’s attorney Jessica Carmichael wrote in a joint filing. “A pre-indictment resolution promotes the public interest by conserving government and judicial resources.”They are asking for a 21-day extension, through October 8. Judge Leonie Brinkema had previously said there would be no extension past her self-imposed deadline of Sept. 17. Details of the working plea agreement are not yet available.More on the David Rush investigationThe case against Rush has brought a spotlight to his relationship with the no. 2 official at the Defense Department, Steve Feinberg, as Jattvibe News reported this week. The FBI reviewed video showing Rush and Feinberg at a residence in the Washington region that is linked to the U.S. Government, according to four people familiar with the video. Feinberg has been interviewed by the FBI, according to two people familiar with the investigation, but has not been accused of any wrongdoing, and the bureau said he is not under investigation. The CIA placed senior officials on leave after Rush’s arrest, Jattvibe News reported. Rush allegedly lied to his employer about his background for nearly two decades. He had a high-ranking job in the spy agency, working on some of the most secret programs in the government. Federal agents seized about 300 gold bars at Rush’s home, federal officials alleged, along with about $2 million in U.S. currency and 35 luxury watches. Rush’s lawyer didn’t immediately return a call seeking comment. The lawyers in the case are under a protective order that bars them from sharing sensitive information in the case.