He was killed in 1980 in the church where he served as pastor, just prior to the celebration of Mass, shot at point blank range.

As a young woman, Spessotto's paternal aunt Maria had been in the process of becoming a nun but was forced to withdraw from the novitiate due to a bone disease.

Spessotto received his confirmation in 1932 while in 1933 he felt a firm call to the priesthood and so insisted to his father that he start his education in preparation for that.

On 16 September 1939 Spessotto was admitted into the novitiate of the Province of Veneto and received the Franciscan habit as well as his religious name of "Cosma".

The war made anesthesia impossible, so he was forced to endure the pain – he asked a nursing religious sister for a crucifix and that she squeeze his hand during the operation, which proved successful.

After his ordination, he requested to be sent to the missions in China, but his mother forbade it due to the volatile tensions with the Communists who had assumed power in 1949.

After three years, he was assigned to serve as the pastor of the Church of St. John the Baptist in the town of San Juan Nonualco.

[3] Spessotto aimed to connect to the local communities while in El Salvador and worked to rebuild a church that an earthquake had leveled in the 1930s.

[1] Yet this was not without complications for he had received his own death threats due to his strong denunciations and opposition to the El Salvadorian military forces.

[1][2] On 14 June 1980 Spessotto had celebrated Mass that afternoon for a slain student in his parish church of St. John the Baptist in San Juan Nonualco, where he had served as pastor for many years.