RIVERHEAD, N.Y. - A Suffolk County judge said yesterday he wants to read transcripts of another court's hearing before he'll consider enforcement of a Connecticut subpoena seeking the grand jury testimony of a former private investigator who worked on behalf of two suspects in the 1975 Martha Moxley murder.

Judge Michael Mullen postponed yesterday's scheduled hearing until next month, by which time he said he will have read transcripts of a previous court hearing. In that hearing, a Nassau County judge ruled that the testimony of the private detective's former employer was not essential to the Moxley investigation.

Connecticut prosecutors had sought testimony from both Sutton Associates owner James Murphy and former employee Willis Krebs, based on allegations that while investigating the Moxley murder for defense attorneys, suspects Michael and Thomas Skakel significantly changed their alibis.

In his ruling last month, Nassau County Judge Jerald Carter said because there appeared to have been no actual conversation between Murphy and the Skakel brothers, Connecticut authorities failed to establish that Murphy was a material witness. In that same ruling, however, Carter said that hearings over which he presided established that two other Sutton Associates investigators - including Krebs - "are witnesses with firsthand knowledge of the alleged Skakel interviews."

Murphy, a former New York City police officer and FBI special agent, was president of the Bishop Services Inc. detective agency when hired in 1992 by an attorney representing Michael Skakel. He remained that lawyer's investigator upon leaving the firm in 1993 to found Sutton Associates, after which time he was also retained by Thomas Skakel's attorney.

Robert Gottlieb, a Commack, N.Y., attorney who represents the Skakels, is seeking to quash Krebs' subpoena - which is now before Mullen - on the basis that any information he gathered while working for the Skakel defense attorneys is privileged. Gottlieb yesterday told Mullen that he plans to call Krebs - who now works for the white-collar crime unit of the Suffolk County District Attorney's Office - as his only witness when the hearing is held March 3.

In the previous ruling, Carter said the claimed attorney-client privilege is a matter that should be decided in Connecticut Superior Court.

Suffolk County Assistant District Attorney Karen Petterson, who is representing Connecticut in the Suffolk court, said she did not plan on calling witnesses. "This matter should not even reach that level to where witnesses are called," Petterson told the judge. In an interview afterward, Petterson said witnesses were not planned because it is usually routine for judges of one state to uphold another state's subpoena in criminal matters.

Connecticut prosecutors are seeking Krebs' testimony because, they allege in court documents, Michael and Thomas Skakel told Sutton Associates investigators that they were either with Moxley at about the time she was murdered or were near the crime scene shortly afterward. Police have identified the murder weapon as a 6-iron from a set of golf clubs owned by the Skakel family.

According to police reports, Thomas Skakel, then 17, told police he left Moxley, his 15-year-old neighbor, at 9:30 p.m. on Oct. 30, 1975, to go home and write a book report for school. Investigators later determined he had no such assignment.

In an affidavit filed with the Nassau court, Connecticut State's Attorney Jonathan Benedict states that Thomas Skakel told a Sutton Associates investigator that on the night of the murder, he and Moxley had a sexual encounter behind the Skakel house that began at about 9:30 or 9:35 p.m. and lasted about 20 minutes. Police established the girl's death to have been at about 9:50 p.m.

According to the affidavit, Michael Skakel, then 15, told authorities that on the night of the murder, he last saw Moxley at about 9:30 p.m. when he left her outside his residence to drive a cousin home and that he went directly to bed upon returning home at about 11:30 p.m., where he remained until the following morning.

The affidavit further states that during his interview with a Sutton Associates investigator, however, the younger Skakel brother said that about 10 minutes after returning home from his cousin's, he went back out and spied on a neighbor, then climbed a tree by the Moxley home near what he thought was Martha's window, where he masturbated. He then went home past the spot where the girl's body was discovered, entering his room through a second-floor window.