The shooting happened around 1 p.m. at the Carolina Crossing Veterinary Clinic on Highway 210.
Authorities say 52-year-old Lile Bernard Parrish shot his 42-year-old girlfriend as she walked toward his vehicle in the parking lot.
Parrish reportedly leaned out of the window and fired one shot, hitting Catryn Bridges in the abdomen.
After the shooting, deputies responded to a house on Matthews Road in Clayton. That's where they found Parrish dead from a self-inflicted gunshot wound.
Neighbors said they heard a gunshot earlier in the day but thought nothing of it.
Bridges was taken to WakeMed and is in stable condition.