The bailiff is an officer of the court charged with the responsibility of enforcing the judgment or order of the court.

A court order telling an officer to bring a prisoner to the court is called a writ of habeas corpus.

The judge.

After. A person is not on probation until they are sentenced to probation by the Court. Why would they get a probation officer until they are sentenced?

The officer that summons people to a trial/court case is called a Warrant Officer.