Arthur March confessed in federal court Monday to helping his son Perry dispose of his wife Janet’s body. It was part of a plea bargain in which Arthur March pleaded guilty to conspiracy to the murder of Janet March’s parents, Lawrence and Carolyn Levine. At the hearing, Arthur March said Perry had confessed to Arthur that he killed Janet in a dispute in their house in Forrest Hills by a blow to the head with a wrench. The sentencing of Arthur March is scheduled for May 1 at 1 p.m. at federal court.