American author, musician and former green beret.
To the general public he is most known for the hit single "Ballad of the green berets"
After his musical career he decided to write a series of novels centered around the character "Casca Rufio Longinius" Who is cursed for piercing Jesus on the crucifix with a spear and is forced to forever remain a soldier until the Second Coming of Jesus Christ.
In the mid 1980s Sadler moved to Guatemala City where he was shot in the head one night in a taxi. He spent 7 months in a coma and died more than a year later.