Authorities released surveillance images Monday of the crime, which happened in the parking lot of Concord Mills last Friday.
"We think the suspect saw a woman who was occupied with her children and saw an opportunity to surprise her," Maj. Allen Overcash said.
The woman was unpacking a stroller when a black man, who was about 6 feet tall, 165 pounds and wearing a ski mask, ran up and put a knife to her throat, police said.
The mother handed over her diaper bag and then ran with her family.
Police said the man may be driving a black sedan, possibly a Lincoln Town Car, with the letter "X" in the license plate.
Other shoppers expressed concerns about safety in light of the incident.
"I will definitely be more aware and cautious of my surroundings as I come in and out of the mall," one woman said.
Anyone with information about the robbery is asked to call Cabarrus County Crime Stoppers at 704-93-CRIME.
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