Uccidi o muori (1966)

A violin-playing gunslinger accidently gets caught in a feud between two families. One of them forces him into a showdown and he kills him. He then must escape from the wrathful family and is accused wrongly for killing 2 deputies. He is saved by an old man, who helps him to get revenge and to prevent the girl he loves from marrying a murderer. Source: SWDB www.spaghetti-western.net