It happened at the Costco in the 700 block of Upper State Road early Wednesday morning.
Police say the thief knew what he was doing and what he wanted when he walked in just hours before closing.
Multiple cases were smashed and little more than glass shards remained after a thief stole $91,000 worth of jewelry from the North Wales Costco on the 700 block of Upper State Road late Tuesday night.
Montgomery Township Police say store surveillance cameras captured an image of the crook, and they are now trying to track him down.
"Even though you don't get a full face view, we believe enough of it is seen so that someone could look at it and see that it looks like someone they know. We would like a phone call so that we can follow up on that," said Detective Sgt. Joseph Bennis.
You see the man on his cellphone getting waved into the discount store around 8:15pm; 15 minutes before closing.
Store cameras capture him wandering around the aisles dressed all in black and wearing a hat like with a logo from DC Shoes.
When the coast is clear, he hides, though police aren't publicly releasing where.
"It's an area where if someone was hiding there, an employee would not look in that particular area to see if anyone was still in there," said Detective Bennis.
The suspect stays hidden for roughly three and a half hours as the store closes and employees do a final sweep to make sure customers are gone.
Around midnight, 15 minutes after the last employee leaves, the man makes his move, grabbing a TV before he crashes it into jewelry cases in complete darkness.
"By the time we see him coming out of hiding, and the time he leaves the store was less than 5 minutes," Detective Bennis said.
He empties 3/4 of the cases' contents and takes off running toward the light of the emergency exit.
When he bursts out of the door, he trips the alarm that notifies police, but he was already gone before they arrived.
He got away with $91,000 worth of jewels like bracelets, diamonds, gemstones, and pendants.
Police are not aware of any similar cases in the area, but are asking if anyone has information that could help them in this case to call Montgomery Township Police at 215-393-6900.