PITTSFIELD – A man wearing a rubber devil’s mask and wielding a knife and a handgun robbed a downtown drugstore Tuesday, stabbing an elderly man and fleeing with thousands of dollars’ worth of narcotics.

Police were searching in Somerset, Penobscot and Waldo counties on Tuesday night for the robber, who fled in a car.

It was the fifth time in four years the independently owned Pittsfield Pharmacy has been the target of thieves, but the first while employees were at work.

“My staff is traumatized,” said owner Ryan Dyer. “It was the most life-threatening experience I’ve ever had.”

Police would not identify the man who was stabbed. He apparently foiled what could have been a hostage taking.

“There is a desperate person on the loose, and we will not compromise the victim’s safety,” said Stephen McCausland, spokesman for the state Public Safety Department.

Before he entered the pharmacy on Main Street at about 11:15 a.m., the robber approached the elderly man’s wife as she was preparing to enter the store. Her husband then came to her aid, striking the intruder repeatedly with his cane and ordering him to leave his wife alone.

The struggle moved to the entrance of the pharmacy, prompting Dyer to shout, “Take the fight outside.” Then a customer spotted the devil’s mask and hollered, “It’s a robbery!” according to Dyer.

Once he realized the man was preparing to rob the store, Dyer told his employees to leave. “About six of them were able to get out the back door. The others were crouching behind counters and in the aisles of the store,” he said.

“He saw that I was the one in charge and then demanded that I give him all the Percocet that we had,” Dyer said. Percocet is a narcotic used for pain relief.

“I gave him some opened bottles of narcotics that were on the counter and we were using to fill prescriptions, but he wasn’t satisfied and wanted more,” Dyer said.

“He stayed in front of the counter, following me as I got the drugs for him. When he was through, he told me that if I followed him, he’d kill me,” Dyer said.

The robber fled, and Dyer said he waited about 10 seconds before running outside to see if he could spot anybody. “There was no one in sight,” he said.

The elderly man, initially unaware of his stabbing, drove to a nearby police station.

At the station, Officer Nicole Sprague started to take his report when she noticed “his front was all covered with blood,” Sprague said. The man was taken to Sebasticook Valley Hospital. His injury was not considered life-threatening.

Dyer said the robber “was definitely high on something when he came in” and that he left with about $10,000 worth of Percocet, Hydrocodone-APAP and generic Darvocet, all narcotics.

Pittsfield police Sgt. Timothy Roussin said the gun used in the robbery may have been a toy. Police believe the robber got into a car parked near a maintenance garage, just a few feet away on Sebasticook Street. The car was possibly stolen, police said, and was likely a silver Buick. Police say they believe the robber acted alone.

He was described as about 20 years old, 5 feet 9 inches tall, 180 pounds, with curly dark hair and a dark mustache and goatee. He was wearing a Halloween mask and a gray sweat shirt.

Police converged on the pharmacy and surrounding area within seconds of the robbery. Among them were officers from the Maine State Police, Newport police, Fairfield police and Somerset County Sheriff’s Department.

A state police aircraft that was part of a speed enforcement detail on Interstate 95 was temporarily diverted to search the area surrounding the pharmacy by air.

The robbery was nearly identical to one exactly one month ago, on Nov. 21, in nearby Fairfield, in which a man similar in description herded employees of a Rite Aid store into the pharmacy section and stole thousands of dollars’ worth of narcotics. That man fled in a stolen pickup truck later discovered abandoned in Burnham.

Fairfield police officers arrived in Pittsfield after the robbery to assist in the investigation.

By late afternoon, the investigation had been turned over to the Criminal Investigation Division of the state police, said Pittsfield police Officer Michael Cote. Six state police detectives were gathering evidence at the scene Tuesday afternoon.

After a burglary at their pharmacy in 2002, Ryan and Christine Dyer installed four additional video cameras and had a special steel door constructed for the rear of the building. All of the previous burglaries were at night, when the pharmacy was closed. As a result, Dyer had installed sophisticated surveillance equipment.

Dyer said the entire robbery was captured on video.

“I managed to keep my cool,” Dyer said, “but I was scared.”