CHARLOTTE – Shoppers are on alert after two teenage girls are targeted. Police say an armed robber used a knife to threaten the victims, ages 16 and 17.

It happened at the StoneCrest Shopping Center in Piper Glen. It’s the second robbery at the location within the past two weeks.

Now, the victim’s mother is giving new details to NBC Charlotte. Off-camera, she said her daughter and a friend had just left a restaurant and were parked in the busy shopping area, when the suspect threatened them with a box cutter.

Shoppers are now on the lookout for more than just sales.

“There’s no place that’s safe anymore, unfortunately,” says Betty, a customer at the shopping center.

The two teenage girls were robbed after eating at Cantina 1511, before leaving the Wendy’s parking lot in the same area at 6 p.m. on Monday. The mother of the 16-year-old victim tells NBC Charlotte the female suspect had a uniform from a nearby restaurant, but police did not confirm any information about that.

“It’s a sad situation when we can’t be safe at six o’ clock in the evening,” says Betty.

It comes within two weeks of another robbery with a 19 year-old male victim in the Target parking lot.

“I’m really surprised because I don’t consider this a high crime area,” says Joan, a customer at the shopping center.

According to crime mapping, there were 177 crimes within a mile of the shopping center since the beginning of the year, but only 18 of them were violent crimes.

Off-camera, the general manager of Cantina 1511 told NBC Charlotte he’s shocked about what happened to the two young customers. He say it was a very busy time and the area is well lit.

Now, the victim’s mother is asking for more video surveillance in the area. “I do agree more security cameras are necessary,” says Betty.

Police say it’s an active and ongoing investigation.

Fortunately, neither of the teenage girls were hurt in the incident. Police have not made any arrests in the case so far.