NEW YORK, JAN. 28 -- In August 1984, the head of the FBI's Denver office sent a puzzled message to the Washington headquarters, saying that he was not sure how far his agents could go in investigating a group opposed to U.S. policy in Central America.

"In spite of attempts by the bureau to clarify guidelines and goals for this investigation, the field is still not sure of how much seemingly legitimate political activity can be monitored," the message said.

A detailed reading of more than 1,200 pages of Federal Bureau of Investigation files made public this week suggests that many of the field offices took an exceedingly broad view of their right to investigate dissidents.

During a five-year probe of the Committee in Solidarity with the People of El Salvador (CISPES), FBI agents investigated nuns, union members and college students; checked up on church forums and Knights of Columbus dinners; photographed protesters at peaceful rallies, and distributed what they deemed offending articles from student newspapers and People magazine.

The Pittsburgh field office, which unsuccessfully sought to plant an undercover agent in the local CISPES chapter, gravely informed then-Director William H. Webster that the group's adherents included "at least one female high school student."

Much of the cable traffic between Washington and the field offices had a decidely political tone, with FBI agents monitoring protesters in 1983 at a speech in Denver by then-White House counselor Edwin Meese III and investigating CISPES plans to demonstrate at the 1984 Republican National Convention in Dallas.

Meese, now attorney general, said today that he would determine whether action is necessary after he receives a report on the surveillance from FBI Director William S. Sessions.

FBI officials have declined to answer specific questions about the CISPES probe, saying much of the information is classified, but insist that they have followed internal guidelines governing domestic security and counterrorism investigations. No CISPES member has been charged with a crime.

Webster, now director of the Central Intelligence Agency, could not be reached for comment.

The FBI also was accused of intimidation during Webster's tenure for attempting to question more than 100 Americans returning from visits to Nicaragua. Many of them had expressed opposition to President Reagan's policies there.

The documents on the probe of CISPES from 1981 through 1985 were obtained through the Freedom of Information Act by the New York-based Center for Constitutional Rights. They include numerous messages in which FBI officials question the motivation of those opposed to administration policy.

The bureau's Milwaukee office, for example, said CISPES is comprised of persons involved in the Roman Catholic Church's sanctuary movement, as well as "the social activist who has been involved in social causes for years. To this type of person, it is desirable to be the object of an FBI investigation as it means he or she must be accomplishing something in their fight against the establishment."

An FBI dispatch from Chicago described the CISPES chapter there as consisting of "the '60s activist type who is often described as 'a rebel looking for a cause.' "

Ann Mari Buitrago of the Center for Constitutional Rights said, "If their purpose is to extinguish the flame of liberty across the land, they got value for their money. If their purpose is to find terrorists, it's a charade."

Despite frequent deletions, the voluminous files indicate that the FBI devoted many thousands of hours to surveillance and undercover work, much aimed at church-related activities and college campuses.

The Baltimore office looked into the Sisters of Mercy Generalate in Silver Spring. The Cincinnati office probed the Friends Religious Society, the Maryknoll Sisters and the Church of the Brothers.

FBI officials in El Paso reported that, when they made "a pretext telephone call" to a local number, "a Hispanic female answered, 'Catholic Conference.' "

Several FBI offices found no evidence of criminal activity but evidently were spurred by Webster's office.

FBI officials in Phoenix reported in 1983 that they had looked into the Tucson Committee for Human Rights in Latin America, "a nonviolent organization," and concluded that "it does not appear that further investigation is warranted."

But Webster's office ordered them to continue the probe, saying the human rights committee "may be a front organization for the CISPES."

When Sen. Robert W. Kasten Jr. (R-Wis.) asked the FBI's Milwaukee office why it was investigating CISPES, he was curtly referred to the Washington headquarters. Referring to numerous inquiries about that probe from the media, the Milwaukee office reported, "All requests for information have been answered with a 'no comment.' "

The extent of the infiltration of CISPES is suggested by an FBI report on the finances of the 250-member chapter in Chicago. "At the last door-to-door canvassing campaign, 29 {Chicago} CISPES members collected $2,117.53," it said.

The documents also show several instances in which FBI agents copied license-plate numbers of individual protesters attending public rallies. The Houston office went a step further, distributing 104 photographs of participants in a 1985 march by the Texas April Mobilization for Peace, Justice and Jobs.

The heaviest barrage of apparently unsupported assertions about CISPES came from the Pittsburgh office, which in 1984 asked Webster's office to approve placement of an undercover agent inside the local chapter.

"The CISPES leadership covertly furnishes . . . funds and materials to the guerrillas in El Salavador, assists in the maintenance of camps in the U.S. for the rehabilitation and reindoctrination of Salvadoran guerrillas . . . either to be returned to the fighting in El Salvador or to remain in the U.S. to establish guerrilla cells," Pittsburgh reported.

The plan was vetoed in Washington on grounds that the proposed undercover agent had transferred out of Pittsburgh. "As targeted group closely scrutinizes a newly introduced member's political beliefs, background and personality, Pittsburgh has no suitable replacement currently available," Webster's office said.

Hugh Byrne, CISPES political director in Washington, called the allegations about training guerrillas "ludicrous" and "nonsense."

As for the widespread surveillance, he said, "We feel outraged. We feel violated. You'd think they would have something better to do with their time and money than investigating an organization that was merely dissenting from the administration's policies."

Excerpts of messages from FBI field offices to the bureau's Washington headquarters about the investigation of the Committee in Solidarity with the People of El Salvador (CISPES):

"From physical observation, the bookstore located at 5412 Jefferson Ave., Newport News, Va. . . . is, in fact, a bookstore open on Wednesday nights and Saturday. A visual inspection of this store indicates that it is also the mailing address for the Young Socialist Alliance, among other groups, and posters and other literature in support of black power and black militancy were seen."

Norfolk

"CASC {Central American Solidarity Coalition} is closely aligned with the Catholic Church's sanctuary program. The sanctuary program is clearly in open violation of federal law and consequently, many CASC members are hesitant to talk to any federal agent. Second, the nature of the people in the group is such that the FBI is not going to receive a great amount of cooperation."

Milwaukee

"It is imperative at this time to formulate some plan of attack against CISPES and specifically against individuals {names deleted}, who defiantly display their contempt for the U.S. government by making speeches and propagandizing their cause while asking for political asylum. New Orleans is of the opinion that the departments of Justice and State should be consulted to explore the possibility of deporting these individuals or at best denying their reentry once they leave."

New Orleans

"Some of the younger 'affiliate' members appear to be politically unsophisticated in that they know little of internationally current events save what they read or hear at their political meetings. Pittsburgh has noted at least two of these members or affiliates both were young females."

Pittsburgh