"Culprit", meaning the guilty party, evolved from this adjective meaning "guilty"
[DOC] [TLE] Guilty, Punishable, Indictable Antonyms: Blameless, Innoc - Net Texts [PAR] You May Remember: From unit 1.8, the -ABLE suffix means able to so someone 
... Culprit (n) - The guilty person or party ... does not carry the same negative 
connotation as the adjective form.