Maryland State Prosecutor Stephen Montanarelli declined yesterday to begin a separate probe of the Dec. 14 fatal shooting of a District police officer by a Prince George's County officer, saying local authorities should be able to properly handle the case.

He said, however, that his office would provide help to local authorities if Prince George's State's Attorney Alex Williams requested it.

"We are out of it," said Montanarelli. "The state's attorney's office in Prince George's is in it.

"The gist of it is . . . we are not going to enter a case where another prosecutor is conducting an investigation," Montanarelli continued. "There is no reason for the state prosecutor to get involved unless there is evidence that the investigation is being conducted improperly."

A spokeswoman for Williams said yesterday that involvement by the state prosecutor's office, which has jurisdiction to investigate misconduct by government officials and employes, is not necessary. Two weeks ago, Williams appointed a special investigator to look into the incident. The county police also are investigating.

The family of D.C. Officer James L. Gordon, saying they feared that political pressures on Williams might result in an incomplete investigation, asked Montanarelli last week to look into the incident separately. Gordon was shot at his Largo home by Prince George's police Cpl. Robert W. Raimond, who apparently mistook him for a burglar.

Gordon family attorney Clayton J. Powell Jr. said he was pleased with Montanarelli's pledge to help in the investigation if needed, and added that the family would be "watching the {local investigation} very closely."

"We are very pleased to know that {Montanarelli} has placed the resources of his office at the disposal of the local prosecutor," Powell said. "Our chief concern is that the case be fully investigated. We don't know whether any outside support should be given {at this time} because the investigation is ongoing."

Gordon was at his home investigating a burglary when Raimond arrived after being dispatched on a burglary report.

Neither officer apparently knew the other was at the scene, police said. Raimond was outside the house when he saw an armed man through a window. Mistaking him for a burglar, Raimond called out for him to freeze, according to a police witness. Police said that, according to the witness' account, Gordon turned and raised his hands in a shooting position, and Raimond shot him once in the chest.

Since the shooting, questions have been raised by Gordon's fellow D.C. officers about whether Gordon was warned properly by Raimond, whether prompt medical attention was administered and about when D.C. police officials were informed and allowed access to the shooting scene.