Edmund C. Horman, whose crusade in investigating his son's disappearance and death in a Chilean coup was portrayed in the film "Missing," died on Friday at Mount Sinai Medical Center. He was 87 and lived in Manhattan.
The cause was pneumonia, his family said.
Mr. Horman flew to Chile in 1973 seeking his son, Charles, knowing that soldiers had seized him but unaware that he had been shot to death.
In his search, he gained entry to the National Stadium in Santiago, where hundreds of prisoners were rounded up in the right-wing military coup overturning the elected socialist Government of Dr. Salvador Allende Gossens.
"Charles Horman, I hope you are out there," Mr. Horman called out through a bullhorn at the stadium. "This is your father speaking. If you hear me, please come forward. You have nothing to fear." There was no response. Charles had been dead three weeks, Mr. Horman learned later.
His frustration in dealing with United States authorities grew into a conviction that they had failed to try to protect Charles when they learned of his arrest, and he accused them of covering up their failure.
Turning the anguish of losing his son into a crusade on human-rights issues, Mr. Horman testified at hearings and spoke to conferences in the U.S. and abroad. "I'm not interested in revenge," he said. "What can revenge do? I don't want this to happen to any American citizens again."
After the original news reports, the case became the subject of "The Execution of Charles Horman: An American Sacrifice" (Harcourt Brace Jovanovich, 1979) by Thomas Hauser. The book was the basis for the award-winning 1982 film "Missing," directed by Constantin Costa-Gavras, in which Jack Lemmon portrayed Mr. Horman.
The film drew widespread attention and prompted an unusual three-page statement from the United States State Department on the eve of the premiere. The Government disputed the film, saying officials diligently sought to find Charles Horman, and they denied any implications of complicity.
Why Charles Horman was killed remains a mystery. A 31-year-old Harvard graduate, he was living in Chile as a film maker and writer. By chance, he went to the Valparaiso coast the day the coup began and saw the invasion.
Fearing for their safety, Charles Horman and his wife, Joyce, sought a flight out of Chile. When he returned home to collect his belongings, soldiers broke in and took him away.
Edmund Horman was born in Manhattan and studied at Columbia University. He worked in engineering and industrial design and owned Jersey Industrial Trucks.
He is survived by wife of 53 years, the former Elizabeth Lazar, and his daughter-in-law, Joyce.