At around 7:00 p.m. the three suspects entered the Oxford Circle Pharmacy on East Cheltenham Avenue and Horrocks Street in the Frankford section of Philadelphia.
They immediately went to the armed security guard.
"During the robbery, they put the gun to the head of the armed security guard who works inside the pharmacy and took his weapon. They threatened to shoot him in the head if he did not give up his gun," Philadelphia Police Chief Scott Small said.
Investigators say the guard complied and the suspect took his .45 caliber gun and began to rob the place.
"They stole about $150 in cash and about 100 bottles of oxycodones and amphetamines," Small said.
The bandits then fled the store and jumped in a white vehicle, possibly a Chevrolet Monte Carlo or Impala.
Detectives believe the bandits knew an armed guard was inside the store.
The entire incident was captured on the store's surveillance system.
However, because the suspects were covered from head to toe, police do not have a good description of them.
"It's very, very brazen for individuals to rob a pharmacy knowing there's a security guard inside," Small said.
The same pharmacy suffered a point of gun robbery four years ago.
During that robbery, hostages were taken which led to a standoff with police.
Two people were charged in that case.
The pharmacy owner hired the armed security guard because of that incident.