A House Appropriations Committee staffer who worked on the panel for former Chairman Jerry Lewis (R-Calif.) announced Thursday that he would not cooperate with a subpoena that apparently was issued in an ongoing investigation of his former boss.

Greg Lankler, a staffer on the Appropriations Subcommittee on Defense, reported to the House last week that he had been served with a subpoena for testimony and documents before a California grand jury.

On Thursday, he wrote to Speaker Nancy Pelosi (D-Calif.) to declare that he would not to comply with the subpoena because it sought legislative material that would be covered by the Constitution’s Speech or Debate Clause. Lankler also said the subpoena sought records that were “not material and relevant.”

For more than a year the Justice Department has been probing Lewis’ relationship with ex-Rep. Bill Lowery (R-Calif.) and his now-defunct lobbying firm, Copeland Lowery Jacquez Denton & White. The firm had a lucrative business obtaining earmarks from Lewis for defense clients and for towns in Lewis’ California district.

— Paul Singer