An Upper Gwynedd veterinarian accused of shooting and killing his mistress has waived his right to a preliminary hearing. 30-year-old David Rapoport of Browning Court in Upper Gwynedd faces two homicide charges in the deaths of 27-year-old Lower Macungie veterinary technician Jennifer Snyder and her unborn child.  Her body was found in March in Lehigh County.  Court documents say the victim’s roommate told police that Rapoport, who is married, was the child’s father, he was angry about her pregnancy, and the two had stopped talking for a while, but they started talking again shortly before she was killed.  Snyder worked at the Maple Hills Veterinary Hospital in Lower Macungie.  She was last seen there two days before her body was found at Trexler Nature Preserve in North Whitehall Township.  Police say they recovered a gun from Rapoport’s blood-stained car.  He worked at the Harleysville Veterinary Hospital, and he grew up in the Lafayette Hill section of Whitemarsh Township.