The FBI supplied information on the progress of two busloads of Freedom Riders through the South in 1961 to the Birmingham, Ala., police department even though it knew the department had been infiltrated by the Ku Klux Klan, according to FBI documents released to the American Civil Liberties Union.

Shortly before klansmen intercepted and burned one bus and severely beat passengers on the other, the chief of the Birmingham FBI bureau called a known klan agent in the police department to tell him of the exact location of the buses, the documents show.

Although more than a dozen members of white hate groups were eventually charged in connection with the violence that day, the policeman passing information to the klan was never charged.

The FBI documents were released to ACLU attorneys for Walter Bergman, who says he was left partially paralyzed by the beating he received May 14, 1961, at the hands of the KKK in Anniston, Ala., 50 miles east of Birmingham.

Bergman, 78, a former Wayne State University professor and Detroit school board official, is using the FBI for 1 million for allegedly failing to prevent the klan violence.

The 3,000 pages of FBI letters, memos and teletypes clearly show that the FBI knew that Sgt. Thomas Cook, of the BPD intelligence branch, was passing information on the activities of the civil rights workers directly to the top leadership of the klan.

An FBI informant who infiltrated the klan identified Cook and then Birmingham Public Safety Director Eugene (Bull) Connor as conspiring with klan leadership to arrange for an attack on the Freedom Riders as their buses pulled up.

Connor reportedly told the klan leaders that police would not be present at the Greyhound and Trailways bus terminals and that police would allow klansmen 15 to 20 minutes to beat civil rights workers.

Light sentences were promised for any klansman caught afterwards, according to the informant, Gary Thomas Rowe Jr., who was the FBI's chief informant in Alabama from 1960 to 1966.

Connor, according to Rowe, told klan officials to beat the Freedom Riders "and make them look like a bulldog got a hold of them."

In fact, news accounts and FBI reports show that when the Trailways bus arrived at the Birmingham terminal, no police were present. Klansmen attacked civil rights workers, news photographers and reporters, beating them with chairs, pipes and baseball bats.

Earlier that day, klansmen intercepted the Greyhound bus at Anniston and set it on fire. Freedom Riders on the Trailways bus, including Bergman were also beaten. The Trialways bus was allowed to continue to Birmingham after the black passengers agreed to sit in the back.

Freedom Riders were beaten again in Birmingham. Rowe, the FBI's informant, was cut across the throat during the fighting. Police made no arrests at the scene.

Because of Rowe's double agent role, the FBI knew at least 10 days before the attack in Birmingham that Sgt. Cook was a klan agent. Cook was instructed by Imperial Wizard Robert Shelton to travel to Anniston to watch for the buses and to notify the Birmingham klan of their progress, Row told the FBI.

Instead, Cook relied on the FBI to keep track of the buses.

An FBI spokesman refused comment on the charge.

Rowe's work as an FBI informant is the subject of a claim against the FBI for $2 million by the ACLU and the family of slain civil rights worker Viola Liuzzo.

Rowe was in the car from which the shots that killed Liuzzo were fired. He surfaced from the undercover FBI role to testify in the trials of three klansmen, who were eventually convicted of violating Liuzzo's civil rights. The three were sentenced to 10 years.

Alabama authorities have recently reopened the investigation to determine if Rowe also fired shots into the Liuzzo car.

The Justice Department is also investigating whether Rowe was an agent provocateur, helping to plan the klan violence that he reported on the FBI