The Christmas Day incident happened at around 11 p.m. Monday, Dec. 25 in Riverhead, on East Main Street.
Riverhead Town Police said a 39-year-old Selden woman left her Ford Fusion running with the heat on outside the Riverhead Stationary store as the 7-year-old child slept in the back seat.
While she was in the store, someone got into the vehicle and drove off.
The incident prompted a large response from the Riverhead and Southampton police departments, as well as New York State Police troopers.
Officers eventually found the car roughly four miles away, in Flanders, with the child still sleeping in the back seat. Police said the child was unharmed.
The Selden woman was arrested on suspicion of endangering the welfare of a child.
On Thursday, Dec. 28, police arrested 51-year-old Shawanna James, who is homeless, for allegedly stealing the car.
James is charged with grand larceny, endangering the welfare of a child, and criminal possession of stolen property.
Click here to follow Daily Voice Brentwood and receive free news updates.