It happened at the DB Jewelers in the Bensalem Center Mall on the 1900 block of Street Road back on December 3rd.
Video of the heist was released on Thursday.
A group of eight people, five women and three men, walked into the store right as it opened.
Police say several of the suspects distracted the clerk, while one woman crawled into the back room.
She had a dress with several pockets, and you can see her stuffing boxes of jewelry into the dress.
Police say the safe was still open, because the store had just opened, and the clerk was still restocking the cases.
The woman was in and out in about three to four minutes, pocketing more than $150,000 in jewelry.
And police believe it's not their first robbery.
"We haven't identified any individual but we believe they're an organized criminal enterprise operating possibly out of New York," said Sgt. Bill McVey of the Bensalem Police.
Police believe these traveling thieves may be of Russian descent and are targeting mom and pop jewelry stores along the East coast. They think this group scouted DB Jewelry a day or two prior to the heist and purposely hit before the jewelry is put out on display.
"The thieves know that the jewelry's going to be in the safe. If it was already out in the case that would make it difficult for them," said Det. Steve Clark.
The thieves actually bought several pieces before and during the robbery to keep the unsuspecting clerks interested.
Police also say they don't have it on video, but they do believe that there was a younger child used to keep the door open, because the door has a locking mechanism.