A Prince George's County prosecutor told a circuit court judge yesterday he needs the testimony of a Washington Post reporter to obtain indictments in connection with alleged rapes and sexual assualts in the county jail. The reporter, Loretta Tofani, was subpoenaed last month to appear before a special grand jury about a series of articles published last September that detailed rapes at the jail.

Attorneys for the paper asked Circuit Judge Arthur M. Ahalt to set aside the subpoena, contending that the demand for her testimony would have an inhibiting affect on her ability to further report the story, and also that it would violate an 1896 Maryland law that protects reporters from disclosing their sources of information in court.

Ahalt is expected to issue a written decision later this week. That decision could quash the subpoena, allow it to stand, or order a further hearing to determine whether or not prosecutors do, in fact, need Tofani's testimony.

Post attorneys also argued yesterday that, because the grand jury meets in secret, Tofani's sources could not be sure what, if anything, she said to the grand jurors. As a result, Post attorney Kevin Baine said, "the flow of information that is coming toward her will come to an abrupt halt."

Because alleged rapists and victims were named in the Post series last September, he added, Tofani has already "in a way presented the case to the state on a silver platter."

Assistant State's Attorney Robert Bonsib argued that Tofani had waived any protection offered by the 1896 Maryland shield law because she had used the names of people quoted in the story. Furthermore, he said, he was "not asking for the names of any sources, just information."

He also noted that Tofani gave a speech to the county bar association about her series on the county jail, suggesting that Tofani had thus set aside any right to secrecy.