You don't see many news conferences like this one.

In the spotlight was Richard Blumenthal, the U.S. attorney for Connecticut, who has been assigned to hunt down leaks about a sensitive undercover FBI investigation that has implicated eight members of Congress on potential bribery charges.

In the audience of questioners were some of the reporters whose sources he is trying to find. The reporters grilled Blumenthal about his contacts with the media.

Yes, he said, he had talked with reporters about investigations, but only for guidance to steer them clear of errors that might injure innocent parties.

Yes, Blumenthal -- a former clerk to Justice Harry Blackmun -- had talked with authors Bob Woodward and Scott Armstrong when they researched their book on the Supreme Court, "The Brethren." But he described himself as "uncooperative" with the two Washington Post reporters.

No, he couldn't say exactly how he would carry out the investigation, because it wouldn't look good to lead details about the leak investigation.

No, he would rather not be referred to as a "plumber," as the famous Nixon White House leak-pluggers of yesteryear were called.

And, no, he said in a brief telephone interview later, he hadn't once planned to write a book about his Supreme Court experiences with a fellow clerk. At least not a nonfiction book. "We specifically rejected the idea of a nonfiction book," he said.

Not surprisingly, Woodward, Amstrong and federal courthouse reporters in Connecticut declined comment when asked if Blumenthal's characterizations about his dealings with them were accurate.

In between the sparring with reporters yesterday, Blumenthal said he had not ruled out subpoenaing reporters and their notes in his inquiry. But he said the government should have a "very, very heavy burden" to show that such a step was necessary.

Blumenthal did say he hoped reporters might cooperate willingly in the investigation.

He also said he would be reporting to both Attorney General Benjamin R. Civiletti and Michael E. Shaheen Jr., head of the department's internal investigations unit, the office of professional responsibility. On Monday, a department spokesman said he'd be reporting only to Civiletti.

Blumenthal said he hopes to find the leakers, determine their motives and make recommendations to prevent recurrences of premature disclosure of sensitive investigations.

Shaheen noted that there have been three or four leak investigations at Justice during the Carter administration. In only one of those was the leaker identified. He was not punished because he had already left the department.

Robert M. Smith, Civiletti's spokesman, and a law school classmate of Blumenthal at Yale, noted that the new leak investigator wasn't totally unfamiliar with the ways of reporters. "He was once a reporter for the Harvard Crimson," he said.

In other developments related to the FBI's "sting" operations yesterday:

Federal officials told a House subcommittee that an Arlington firm, Olympic Construction Corp., didn't receive favored treatment in getting government contracts because of its association with the FBI.

The Washington Post disclosed last week that Olympic was set up two years ago with seed money from the FBI and that a subsidiary was used to seek out bid-rigging in government contracts.

An attorney for Joseph Sylvestri, one of the middlemen who allegedly brought members of Congress to FBI agents posing as representatives for Arab businessmen, said his client was asked to target certain public officials.

"Other times it was just a blanket request to meet anybody -- a wholesale slaughter," Alfred G. DeCotiis told The New York Times. The lawyer added that Sylvestri, of Keyport, N.J., was not a government witness in the cases.

Justice Department sources declined to comment on DeCotiis' statements, but said it is the procedure in any undercover operation that the middleman, not the undercover operative, chooses the target to be brought in to the "sting."

Another alleged middleman, Alex Feinberg, of Cherry Hills, N.J. was asked to take a leave of absence from the Delaware River Port Authority. He was appointed to the post in 1975 on the recommendation of Sen. Harrison A. Williams Jr. (D-N.J.). Feinberg is alleged to have accepted Williams' share of a secret stock deal contrived with the FBI agents.

The Associated Press reported that the FBI has evidence that organized crime bosses planned a summit meeting recently to carve up new territorial boundaries for their operations.

The meeting apparently was canceled because of recent disclosures of FBI undercover operations against organized crime.

AP also reported -- in an unrelated case -- that some Immigration and Naturalization Service employes have been charged in sealed indictments and about 15 others are under investigation for receiving kickbacks in return for immigration papers.

The evidence was obtained from hours of taped conversations with a person convicted of bribery.