The incident happened at around 11 p.m. Monday, Dec. 25 in Riverhead, on East Main Street.
Riverhead Town Police said the 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 with the child still inside.
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.
The child was still sleeping in the back seat and was unharmed, police said.
A Suffolk County Police K-9 unit searched the area but was unable to locate a suspect.
Police arrested the Selden woman on suspicion of endangering the welfare of a child. Her name was not released to protect the child’s identity.
Anyone with information in the case is asked to contact the Riverhead Town Police Department at 631-727-4500.
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