SANTIAGO, Chile — The United States military intelligence services played a pivotal role in setting up the murders of two American citizens in 1973, providing the Chilean military with the information that led to their deaths, a court here has ruled.

The recent court decision found that an American naval officer, Ray E. Davis, alerted Chilean officials to the activities of two Americans, Charles Horman, 31, a filmmaker, and Frank Teruggi, 24, a student and an antiwar activist, which led to their arrests and executions.

The murders were part of an American-supported coup that ousted the leftist government of President Salvador Allende. The killing of the two men was portrayed in the 1982 film “Missing.”

The ruling by the judge, Jorge Zepeda, now establishes the involvement of American intelligence officials in providing information to their Chilean counterparts. He also charged a retired Chilean colonel, Pedro Espinoza, with the murders, and a civilian counterintelligence agent, Rafael González, as an accomplice in Mr. Horman’s murder.