Cuba's secret service was behind the assassination of President Kennedy, according to a German filmmaker who claims to have eyewitness evidence solving one of the greatest mysteries of the 20th century.

Wilfried Huismann, director of a documentary to be screened on German public television tonight, said he has witnesses saying Lee Harvey Oswald, was acting on behalf of G2, Cuban President Fidel Castro's foreign intelligence service.

Mr. Castro, said Mr. Huismann, had found out that Mr. Kennedy wanted to have him assassinated and decided to pre-empt him. Cuba's involvement was covered up by Mr. Kennedy's successor, President Lyndon B. Johnson, because that revelation could have led to war, according to Mr. Huismann's documentary. Mr. Kennedy was fatally shot in Dallas on Nov. 22, 1963.

"We found direct witnesses, former officers of the Cuban state security, who knew about the contacts with Lee Harvey Oswald," Mr. Huismann, who spent three years researching the film, "Rendezvous With Death," told Deutschlandfunk radio in an interview on Wednesday.

Mr. Huismann interviewed aides of Mr. Kennedy and Mr. Johnson, including Alexander Haig, a military adviser to both Mr. Kennedy and Mr. Johnson who became secretary of state in 1981. The film is based on testimony from former U.S., Cuban and Russian agents, as well as KGB and Mexican files.