A string of particularly violent robberies at cell-phone stores has police concerned about the safety of employees and customers.

The 12 robberies at Metro PCS phone stores throughout the city have unfolded since Nov. 29 and the robbers are extremely brazen, Chief Inspector William Colarulo said.

"They would order the employees to the ground and they would put the gun to their head or the knife to their head. And then they would demand access to the safe," Colarulo said. "It's a miracle that there have been no injuries as a result of these robberies."

Officers James Morrison and Sylvester White arrested two adults and three juveniles after a robbery at a store at 1601 E. Erie Ave. on Saturday afternoon. The suspects were caught nearby on Venango Street.

About the same time, a store at 1400 S. Broad St. was robbed.

At a news conference yesterday, police showed a surviellance video of the robbery at 3132 Kensington Ave. at 11:45 a.m. on Dec. 20. Five young men enter the store briskly, one with a machete and at least one with a gun.

The robbers order an employee to the floor, with the machete pressed to his head as he crouches with his hands in the air.

Another employee is ordered down as well and she is clearly frightened, covering her face with her hands as the robbers quickly jump the counters, go through the cash registers, and demand access to the safe.

Within two minutes, the men flee in a getaway car parked outside.

Police believe the stores have become targets because customers are allowed to buy phones and phone plans for cash. On Dec. 8, $5,000 was taken from a store at 2320 N. 29th St. The same store was robbed again Dec. 19. In all, about $18,000 was stolen.

A store at 6451 Haverford Ave. also was robbed twice and police believe the bandits were planning a third robbery when one of the employees called police before the men entered the store.

Anoyone with information about the robberies is asked to call detectives at 215-686-3397.

Contact staff writer Barbara Boyer at 215-854-2641 or bboyer@phillynews.com.