Safeway in Dublin was locked down for about an hour Thursday afternoon, from about 12:40 to 1:40 p.m., after the pharmacy was robbed, witnesses said.
A Salvation Army volunteer outside the store said police told her to move her kettle and stay away from windows during the lockdown.
As of about 2 p.m., technicians from Dublin police were still on the scene processing evidence.
"They got some prescription medications, some Norco and a different derivative of Oxycontin, Percocet," said Dublin Lt. Steve Brown.
He described the suspect as 5 feet 3 inches to 5 feet 5 inches tall, weighing around 200 pounds.
Police are uncertain whether the suspect is the same one involved in a string of recent pharmacy robbery attempts, because witness descriptions are varied.
"It could be the way it's perceived, but there could be more than one, Brown said.
The store is located at 7499 Dublin Blvd.
Pleasanton police are investigating two attempted pharmacy robberies that may be related to each other, although there is some variation in the description of the suspect.
At 12:37 p.m. Thursday Pleasanton Police Patrol Units responded to the Rite Aid Pharmacy at 2819 Hopyard Road, according to a news release from the Police Department.
A pharmacy employee told police a lone suspect entered the pharmacy and presented a note claiming to have a gun and demanding narcotics. The staff did not comply and the suspect fled the store on foot.
No weapon was seen and no one was injured during this incident.
The suspect is described as an unshaven white male in his early 30s, 5 feet 6 inches to 5 feet 3 inches tall and weighing 130 to 140 pounds. He was described as having a very red facial complexion and was wearing a light brown jacket and brown beanie cap.
A similar robbery attempt occurred at about 6:15 p.m. Wednesday at Lucky pharmacy at 6155 W. Las Positas Blvd.
In that incident, a lone suspect also presented a demand note for narcotics and claimed to have a gun. That suspect also fled without getting any drugs. As with today's incident, no weapon was seen and no one was injured.
That suspect is described as an unshaven white or Middle Eastern man, 30 to 40 years old, about 5 feet 8 inches tall and 190 lbs. He was wearing a blue shirt and gray sweat pants.
Anyone with information about these crimes is asked to call the Pleasanton Police Department at 951-5100.
Pleasanton police are working with police from Dublin and Livermore to determine if the the attempted robberies are related to recent similar crimes in those jurisdictions, including a Dec. 12 attempt at CVS pharmacy on Regional Street in Dublin.