Poindexter, North May Be Called Before Grand Jury : Iran-Contra: Prosecutors are seeking missing links in the case to close the books on the scandal. New indictments would be unlikely.

Former National Security Adviser John M. Poindexter faces a possible grand jury appearance after his June sentencing on Iran-Contra convictions, sources say, as prosecutors chase elusive information vital to writing a final report on the scandal.

New testimony from both Poindexter and former National Security Council aide Oliver L. North could be compelled under a grant of immunity from prosecution, the sources said.

While such grand jury appearances might provide missing links to the cover-up and help prosecutors close the books on the more than 3 1/2-year-old scandal, new indictments would be unlikely, they said.

That was the consensus drawn from a series of interviews with sources in and out of government in the wake of Poindexter’s conviction Saturday on five charges of obstructing Congress, lying to Congress and conspiring with others to deceive Congress and to destroy government documents.

These sources, who asked that their names not be used, said Poindexter’s weekend conviction is significant because it provides a focus for the next, and possibly final, phase of the Iran-Contra prosecutors’ criminal probe.

The conspiracy conviction was the first courtroom confirmation that Poindexter; North; William J. Casey, the late-CIA director; former National Security Adviser Robert C. McFarlane, and others worked illegally together.

The conspirators’ goals, the investigators have said, were to conceal from Congress evidence of the diversion of Iran arms sale money to the Contras, the U.S. role in a Hawk missile shipment to Iran and North’s military support for the Nicaraguan rebels during a time when all U.S. aid to the Contras was banned by Congress.

Mary Belcher, a spokeswoman for the Iran-Contra prosecutor’s office, said that independent counsel Lawrence E. Walsh would not comment on matters that may or may not pertain to grand juries.

Nevertheless, North, Poindexter and possibly former CIA station chief Joseph F. Fernandez may be compelled to give grand jury testimony about the scandal, the sources said. All three testified to Congress after being granted immunity from prosecution.

Getting immunity for North would give Iran-Contra prosecutors their first opportunity to conduct a wide-ranging interrogation of the former Marine officer outside the constraints imposed by a courtroom trial setting.

Poindexter, like North, gave immunized testimony to Congress in 1987, saying he did not inform then-President Ronald Reagan about the diversion of Iran arms sale proceeds to the Nicaraguan Contras.

But the former national security adviser did not testify at his own trial, and a grand jury appearance would be the first opportunity Iran-Contra prosecutors have had to question him in that setting.