The Collaborative International Dictionary of English v.0.48:

Perpetrator \Per"pe*tra`tor\, n. [L.]
   One who perpetrates; esp., one who commits an offense or
   crime.
   [1913 Webster]

WordNet (r) 3.0 (2006):

perpetrator
    n 1: someone who perpetrates wrongdoing [syn: perpetrator,
         culprit]