The 17-year-old suspect has not been identified by police.
The carjacking happened around 7:45 p.m. Monday at the intersection of Greenhill Avenue and Lancaster Avenue in Wilmington, Delaware.
Tiffany Righter parked in front of a Sunoco station there, and ran inside to make a purchase. Her baby, Zion, was in the car.
"When I came out he was just shutting my door. I banged on the door, 'My baby's in the car, my baby's is the car.' He pulled off anyway," Righter said.
About a half hour later the car, along with little Zion, was found a few blocks away at Lancaster and South Bancroft Parkway.
He was fast asleep and unharmed.
Police say the suspect was identified through witnesses, and police say he was also identified by Righter. The teen was arrested after police executed a search warrant at his home in the unit block of Delvin Terrace.
The suspect was charged with Carjacking 1st degree and Kidnapping 2nd degree.
He was later sent to the New Castle County Detention Center for lack of $40,000 bail.
