culprit

someone who has done something wrong or something responsible for a problem ผู้กระทำความผิด

"I want to ask why officials protecting the forest are in jail, and why the culprits [who killed the elephant] are still free," said Mr Chaiwat.

Police expected to name the culprit behind the bombings in a couple of days.

On the same day Dubai's Emirates, one of the world's fastest-growing airlines, reported half-year net profit tanked 76% on 2010 to 827 million dirhams ($225 million) with higher fuel costs a major culprit.