A teenage thief stole a Tower Grove South mom's car on Christmas morning — moments after she'd strapped her baby son in the backseat, authorities say.
The 26-year-old mom was warming up the car and walked back to her home in the 3400 block of Spring Avenue to lock the door, police say. She turned around just as the teen jumped into her car and sped off with her child.
The sixteen-year-old drove about a block before he pulled over in the 3400 block of Giles Avenue, abandoned the infant on the doorstep of a house and took off again, according to police.
The teen was spotted by officers shortly after.…