Authorities are investigating whether a former federal prosecutor manufactured threats against herself and a magistrate during the extradition case of two Sikhs accused of terrorism in India, the U.S. attorney said Monday. A search of former prosecutor Judy Russell's house revealed similar threatening messages in a travel bag, said U.S. Attorney Samuel A. Alito Jr. An FBI laboratory analysis concluded that typewritten characters on envelopes containing the threats matched those on the prosecutor's 1983 application to the U.S. attorney's office, Alito said. The typewriter matching the print also was found in her house, he said. Ms. Russell was in charge of handling the Sikhs' case as an assistant U.S. attorney until leaving the office last summer to enter private practice. She received a temporary appointment as a special assistant after that, so she could continue to handle the case. She had submitted sealed information to U.S. Magistrate Ronald J. Hedges during the weeklong hearing about the extradition in February. Alito revealed Monday that they consisted of three typewritten envelopes containing the messages and one handwritten envelope, all purportedly mailed to her Newark law office. One of the letters addressed to Ms. Russell said: ``Don't get dead. Don't go to court.'' Hedges also received a threatening letter, two weeks before the extradition hearing, Alito said. The revelations that Ms. Russell was under investigation came during a court session requested by Alito to ``correct and supplement'' the record regarding the threats. Robert J. Fettweis, Ms. Russell's attorney and former colleague in the U.S. attorney's office, said she was in a private hospital. He would not comment on any aspect of the case or the nature of her illness. Alito said Ms. Russell had not been charged. The Justice Department's Department of Public Integrity was handling the investigation, he said. The extradition hearings took place Feb. 1-5 under extraordinary security, including sharpshooters on rooftops, which federal officials said was prompted by ``intelligence'' received by investigators. Hedges ordered that the men, Ranjit Singh Gill, 25, and Sukhminder Singh, 26, could be extradited. That ruling was being appealed. Alito said the revelation about Ms. Russell's alleged involvement in the threats had no affect on the outcome of the extradition case, but said he would seek a new hearing ``only because we want to avoid any appearance of impropriety.'' The Indian government charges that Singh plotted the revenge assassination of a retired general who led the bloody 1984 assault against Sikh militants occupying the Sikhs' holiest shrine, the Golden Temple in Amritsar. Gill was charged in the killing of a Parliament member. Singh's attorney, Ronald Kuby, called the affair ``clearly the most astounding thing I've heard.'' He has accused the Indian government of being behind the ``threats'' to poison the atmosphere against the two Sikhs.