The robberies of Ben Bridge Jewelers at Frisco's Stonebriar mall Tuesday and at NorthPark Center in June appear to be related, police said Thursday.

Frisco police released the surveillance video and the 911 call of the Stonebriar robbery and announced a $12,000 reward.

The video shows five men walking single file into the Ben Bridge at Stonebriar at about 10:20 a.m. Tuesday. One robber held the unarmed security guard while the four others used mallets and their feet to smash the display cases.

As they nervously turned toward the door every few seconds, the men took scooped up property, including Rolex watches.

All were wearing gloves; one of the men paused after helping smash display cases to remove some gloves from his pocket and put them on.

About 90 seconds after they started, the robbers fled through the store's front door and disappeared into the mall.

Frisco police said the incident appeared to be related to another robbery at NorthPark Center earlier this year.

In June, a group of robbers entered a Ben Bridge Jewelers at NorthPark Center in the morning and stole more than $260,000 worth of watches. In that incident, some sort of hammer was used to smash the cases, Dallas police said.

The value of the property stolen in the Stonebriar incident was not immediately available.

Frisco police said provided the following descriptions of the robbers:

Robber #1: Black male with stocky build wearing a blue Dallas Cowboys baseball cap, a long-sleeved white and plaid button-up shirt, dark pants and shoes and carrying a mallet with a wood handle.

Robber #2: Black male with stocky build wearing a dark-colored baseball cap, white-short sleeved shirt with writing on the front and dark pants and shoes.

Robber #3: Black male with stocky build wearing a dark-colored baseball cap, dark long-sleeved shirt, dark pants and shoes, white sock and carrying a mallet with a wood handle.

Robber #4: Black male with a thin build wearing a light-colored baseball cap, light blue long-sleeved button-up shirt, light-colored pants, dark shoes and carrying a light-colored bag.

Robber #5: Black male with thin build wearing a dark-colored baseball cap, dark long-sleeved shirt or pullover, a white shirt underneath, blue jeans and dark shoes.

Anyone with information was asked to call Frisco police at 972-292-6010.