Officers responded to the station at 485 Post Road East in Westport around 3:45 p.m. Monday, Jan. 20, authorities said.
The victim told police that as they were pumping gas, a young man slipped into the driver's seat of the black 2022 Mercedes-Benz GLS unnoticed.
The owner tried to get the suspect out, but they opened the car door and knocked them to the ground before speeding off in the stolen vehicle toward Compo Road North, police said.
The victim declined medical attention.
Westport police urge anyone who witnessed the theft or has information on it to contact investigators at 203-341-6000.
Click here to follow Daily Voice Branford and receive free news updates.