RTE star Joe Duffy, pictured, will narrate a radio documentary chronicling one of the most high-profile incidents of the Troubles, in which a father of two was killed by the Provisional IRA.
German industrialist Thomas Niedermayer vanished at 11pm on December 27, 1973, after two men arrived at his home in Glengoland, Belfast. In March 1980, his remains were found in a rubbish tip at Colin Glen, on the outskirts of west Belfast.
In the documentary, Mr Niedermayer's two grandchildren, his only remaining relatives, talk about what happened to their family after his death.
On the night he disappeared, his 15-year-old daughter Renate answered the door. Two strangers asked her to get her father on the pretext that they had damaged his car.
He went outside but was bundled into a car and was never seen alive again. In 1981, a Belfast man was jailed for 20 years for his manslaughter.
Several other members of his family killed themselves in the years following his death.
'A Knock on the Door' is on RTE Radio One on February 16 at 6pm.