[3] It is in this context, in 1957, that a local chairman of the South Tyrolean People's Party and local council head of Frangart, Sepp Kerschbaumer, became disenchanted with his party attitude toward Italianization and founded the "South Tyrolean Liberation Committee" (Befreiungsausschuss Südtirol), which began a progressive campaign of confrontation with Italian authorities, initially limited to the distribution of leaflets or the display of the banned flag of Tyrol.

[4] On 25 June 1967, at 03.40 am, a sentry watching the outpost of Forcella Dignas, near San Pietro di Cadore, heard a powerful blast from the direction of Cima Vallona, a pass in the Alps 2,532 meters[5] above sea level.

The serviceman radioed to his superiors at Santo Stefano di Cadore, who sent in a mobile patrol consisting of Alpini, Finanzieri and ammunition technicians.

When the men were only 70 meters from the place, radio operator Armando Piva, an Alpino of the "Val Cismon" battalion, stepped on an explosive device hidden in a gravel pile.

[6] According to Italian authorities, the BAS group who set up the ambush departed from Obertilliach, in the Austrian Tyrol, and reached Cima Vallona from a clandestine mountain path.

[7] Five members of the BAS were indicted for the killings: Norbert Burger, Peter Kienesberger, Erhard Hartung, Egon Kufner (a sergeant in the Austrian Army) and Hans Christian Genck.

Austrian authorities, under pressure from the Italian government, brought Kienesberger, Hartung and Kufner to trial, but eventually found them not guilty for lack of evidence.