You searched for: “provocateur
provocateur (s) (noun), provocateurs (pl)
1. Someone who arouses trouble, causes dissension, or is an agitator: The provocateurs decided to stir up trouble during the rally in order to distract the people so they would be able to steal their money and other valuables during the ruckus.
2. A person employed to associate with suspected illegal individuals or groups, and by pretending sympathy with their aims, incites them to commit incriminating acts that will make them liable for legal punishment: In the crime novel which Jane was reading, the police wanted a provocateur to incite a suspected criminal to commit a crime by selling drugs so they could arrest him.
3. Etymology: a shortened form of agent provocateur, "a person hired to make trouble"; from French, provocateur which came from from Latin provocator, "challenger"; from provocare, "to call forth, to challenge"; from pro-, "forth" + vocare, "to call".

"A U.S. provocateur's road to handcuffs"

James O'Keefe III made a national splash last year when he dressed up as a pimp and trained his secret camera on counselors with the liberal community group Acorn, eliciting advice on financing a brothel on videos that would threaten to become Acorn's undoing because they gave him and his partner, Hannah Giles, who posed as a prostitute, suggestions on how he could avoid being prosecuted by authorities.

—"How a guerrilla videographer ended up in handcuffs"
by Jim Rutenberg and Campbell Robertson in the
International Herald Tribune; February 1, 2010; pages 1 & 8.
Word Entries containing the term: “provocateur
agent provocateur (s) (noun); agents provocateurs, agent provocateurs (pl)
1. A person who is employed to encourage people to break the law so they can be arrested and prosecuted: The government used agents provocateurs to try to undermine the opposition party so they would lose the election.
2. A secret agent implanted in an organization; such as, a trade union or political party, to incite its members to actions or declarations that will result in penalties or punishment for them: In the story that Jim was reading, the secret service decided to ask a young woman to be an agent provocateur in order to provoke a suspected person to perform an illegal deed which would then result in his conviction.