An appeals court ordered a new trial after finding a judge improperly denied the defendant’s challenge for cause for a potential juror, a federal agent, who said he often worked on cases in tandem with county prosecutors.

The Appellate Division, Third Department panel concluded in People v. Greenfield, 104378, that reversal was warranted because the defense was forced to use a peremptory challenge to remove the agent, and the defense exhausted its allotment of peremptory challenges before a jury was seated for the 2011 trial of David Greenfield in Rensselaer County Court.