It happened on Saturday around 2 p.m. The suspects were in and out within 25 seconds.
Police arrested a 17-year-old female but are searching for three others in connection with the retail theft.
"Four individuals went into the store and they just began attacking the high-end handbags section. When loss prevention started confronting them, there was an indication there was a knife involved by one of the suspects," said Lower Merion Police Lt. James Baitinger.
Three of the suspects were able to get away with about 15 bags.
Police shared an image of a black Dodge Durango the suspects were seen driving.
Lt. Baitinger says the SUV has been connected to other similar crimes.
"This same vehicle was involved in a theft on the 4th of June in East Rutherford, New Jersey. We really want anyone with information to help us," said Lt. Baitinger.
On Thursday afternoon, business was back to normal, but customers said there was a noticeably higher presence of security inside the store.
Shoppers expressed concerns.
"It's surprising to hear here at this location. Never experienced anything like it when I worked here. But as you see on social media, other platforms, kids get the idea they can also do it," said Jeisy Rodriguez, of Haverford Township.
"This area, it's definitely it's bold. Especially doing it, getting away; and now you're just on the run," said Eric Blackwell of Woodbury, New Jersey. "I think we need to give kids something better to do, versus stealing and sitting outside doing negative stuff that's hurting the community."
Police believe all the suspects are teenagers.
They are reviewing in-store surveillance and working to identify them.
The teenager taken into custody is facing felony theft charges.