What started out as an investigation into whether the California Supreme Court delayed a controversial decision for political reasons may have become an inquiry into the news reports that sparked the investigation.

Los Angeles attorney Seth Hufstedler, special counsel for the commission conducting the inquiry, said he intended to question reporters who had written about the decision as well as critics of the court.

So far, Hudstedler and his associates have attempted to interview Carol Benfell, a reporter for a Los Angeles legal newspaper, and George Nicholson, a conservative columnist and executive director of the California District Attorneys Association.

Benfell is the San Francisco correspondent for the Los Angeles Daily Journal, which had an extensive early account of the incident. She said she told Hufstedler that she "stood by my story."

Nicholson at first agreed to an interview, then changed his mind.

'I told them I considered the direction of the inquiry very dangerous, an invasion of the First Amendment, the [California] shield law and other constitutional protections," Nicholson said. "It's going to have a chilling effect on people who write about the court."

At issue is whether the California Supreme Court held up a decision overturning the state's "use a gun, go to prison" law until after the Nov. 7 election last year.

The Los Angeles Times reported on election day that the court had agred to overturn the 1975 law, in a case known as People vs. Tanner, but was withholding its decision until the balloting. The newspaper quoted "well-placed court sources."

According to these sources, the decision was delayed by veteran Justice Matthew O. Tobriner, who was actively supporting Chief Justice Rose Bird in her effort to win confirmation from the voters. Bird won a narrow victory, and some of her critics contend she would have been defeated if the gun-use decision had come out earlier.

Six weeks after the election, the court struck down the gun-use law with Tobriner writing the majority opinion. Bird voted with the 4-to-3 majority and wrote a concurring opinion holding that the legislature had unconstitutionally invaded judicial discretion by passing the "use a gun, go to prison" law.

The decision and its alleged delay touched off a storm of protest, including demands for a formal investigation.

Legislation was introduced to reestablish the original law, which Gov. Edmund G. (Jerry) Brown Jr. at the time of the signing had called "a clear message to every person in this state that using a gun in the commission of serious crimes means a stiff prison sentence." Some newspapers that had editorially supported Bird's confirmation strongly criticized the court. Finally, the court agreed to rehear the Tanner case, on which it has yet to announce a second decision.

While this was happening, an inquiry was launched by the state Commission on Judicial Performance into whether the court had help up the original decision. But the investigation had been under a cloud from the beginning because five of its nine members are appointed by the court they are supposed to be investigating.

In addition, at least two of the other four members are considered friends of the chief justice. On of them donated $200 to the campaign waged for her confirmation.

There are those close to the investigation who also say it has been frustrated by the unwillingness of justices, especially Bird, to provide key information while the Tanner case is pending. Some commissioners hope that the court will remove this roadblock by issuing its second Tanner decision before a public hearing is held in the inquiry.

In any event, Hudstedler said he is now turning to every possible source for information and that he intends to interview reporters for the Los Angeles Times and The Washington Post about their articles. Hufstedler said he would respect California's shield law, which protects confidentiality of news sources. But he declined to rule out the possibility that reporters would be subpoenaed.

The Washington Post reported on Nov. 23, 1978, that mounting criticism of the then-unannounced Tanner decision would prompt a formal inquiry by the Commission on Judicial Performance into the charges of political delay.

A day later, Bird asked the commission to investigate the charges.

Bird issued a brief statement at the time of the original report in the Los Angeles Times denying any improper action. But she has consistently refused to be interviewed about the case or any other subject since her election. CAPTION: Picture, CHIEF JUSTICE ROSE BIRD . . . gun law ruling issued after election