Kadir said the men, all Sunni Arabs, were found with a letter from a former deputy of Saddam Hussein's, Izzat Ibrahim al-Duri, urging them to kill Raid Jouhi.
Juhi is the chief investigative judge on the Iraqi High Tribunal, which is empowered with judging former regime officials, including Saddam Hussein, for crimes against humanity, war crimes, and genocide.
The trial of Hussein and seven co-defendants resumes on 28 November after a five-week recess.
Former U.S. Attorney General Ramsey Clark and ex-Qatari Justice Minister Najib al-Nauimi are expected to join chief Iraqi lawyer Khalil Dulaymi for the proceedings, which have until now been entirely Iraqi-run.
(compiled from wire reports)