Michael Proctor, the former lead investigator in the Karen Read case, was heckled outside the courthouse in Dedham Tuesday.

Proctor was assigned to investigate the death of Read’s Boston police officer boyfriend, John O’Keefe. He was relieved of his duty without pay this past summer after a mistrial was declared in Read’s murder case and his last day with the Norfolk District Attorney’s Office followed soon thereafter.

King is one of at least three defendants seeking information about Proctor from the federal materials, which are under a secrecy order.