A lawyer representing a doctor accused of negligence in the death of a 6-month-old boy said he was shooting at a moving target as the plaintiffs’ team changed its reasoning during trial as to why his client should be held responsible.

Peters & Monyak partner Jonathan Peters said his client, a pediatrician, was initially accused of improperly prescribing a medication that federal regulators declared should not be administered to such a young child. When that claim didn’t seem to gain any traction, he said, the plaintiffs shifted to painting the doctor as failing to diagnose the seriousness of the child’s condition in the first place.