The State Department intervened last summer to cut off a round of unauthorized, freelance diplomacy in Bosnia by Cody Shearer, brother-in-law of Deputy Secretary of State Strobe Talbott, according to senior State Department officials.

The officials said the department was responding to reports from diplomats in the region that Shearer -- twin brother of Talbott's wife, Brooke Shearer, and brother of former ambassador to Finland Derek Shearer -- was telling Bosnian Serb and Muslim leaders that the United States would support partition of Bosnia and was even showing maps of the purported partition plan.

The United States has long opposed partition of Bosnia. Ambassador Robert Gelbard, the official responsible for overseeing implementation of the Bosnian peace agreement, told the leaders of all Bosnian factions that Shearer's reported plan had no backing in Washington, and Talbott himself finally wrote a letter to Shearer asking him to cease his activities, officials said.

Earlier, Shearer had reportedly been negotiating through a Bosnian contact for the surrender of former Bosnian Serb leader Radovan Karadzic, who has been indicted by the International War Crimes Tribunal at the Hague. U.S. officials said they tolerated that -- without knowing whether Shearer had any prospect of success -- because the capture of Karadzic would be in accordance with U.S. policy.

But when word filtered back to Washington of the partition discussions -- which reportedly had elicited expressions of interests from the Bosnian Muslim leadership -- "we said, enough is enough," a senior official said.

At no time was Shearer authorized to negotiate on behalf of the U.S. government, and Talbott knew nothing of his activities until he was informed by Gelbard, senior officials said.

Shearer, who describes himself as a freelance journalist and runs a tiny Washington office known as the Institute for International Mediation and Conflict Resolution, said the entire story is "crazy" and "absurd." He said his only role was to put friends at the Hague tribunal in contact with a physicist from Montenegro who had information that might lead to the capture of war crimes suspects.

He said he knew nothing of any supposed partition plan. He said Talbott did write him a letter saying that people were "misconstruing" the family connection, but "it made no sense. I couldn't figure out what he was talking about."

Shearer's alleged activities in Bosnia were reported this month by David Bossie, the former chief investigator for the House investigation of Clinton-Gore campaign activities chaired by Rep. Dan Burton (R-Ind.).

Bossie, who has a reputation among journalists for accurate if ideologically loaded information, now produces "The Dave Bossie Investigative Report," an Internet newsletter. The Shearer story appeared in the first edition of the newsletter and was excerpted in the Washington Times.

The web of connections among the players in this mini-drama goes beyond Bosnia. While Bossie once worked for Burton, Brooke Shearer worked with investigator Terry Lenzner, who was hired by lawyers for President Clinton in connection with the White House sex scandal. Cody Shearer said published reports that he, too, worked for Lenzner are inaccurate.

Bossie also alleged -- and Shearer and the State Department denied -- that Shearer asked his brother Derek to channel a letter that had been sent to him by Karadzic on to Gregory Craig, then the State Department's director of policy planning and now Clinton's senior counsel in the House Judiciary Committee's impeachment investigation. CAPTION: David Bossie, former Hill investigator, reported that Cody Shearer, Brooke Shearer's twin, was conducting informal diplomacy in Bosnia. ec CAPTION: Officials said Deputy Secretary of State Talbott urged in-law to stop. ec