MANCHESTER — Police are looking for a woman who held up a Western Avenue pharmacy Saturday.

Nobody was injured in the holdup at Rite Aid, but the woman “threatened violence” before fleeing with an undisclosed amount of prescription medication, said Sgt. Frank Hatch of the Kennebec County Sheriff’s Office.

The robbery was the second at the store – and the sixth in the capital area – in just over a month.

Saturday’s robbery was reported around 3:15 p.m. when a woman wearing baggy men’s clothing entered the store, approached the pharmacy and demanded painkillers, Hatch said. She was given pills and fled. Police with a dog tracked the woman from the store, but were unable to find her, he said.

“The track led to some additional evidence,” he said. Kennebec County Sheriff Randall Liberty said the evidence included clothing.

Winthrop police, Maine State Police and Kennebec County sheriff’s deputies converged on the area to help with the search.

The robber was described as about 5 feet tall with brown hair. Hatch did not immediately have a weight estimate.

“She was wearing stuff that covered up how much could be seen,” he said.

It is the second time in just over a month that the store has been robbed. A man walked into the pharmacy on Aug. 3 and demanded prescription drugs. Thomas Bourque, 31, of Belgrade, has been charged in connection with that robbery.

There were a record 56 pharmacy robberies in Maine in 2012, but the number of incidents dropped to a handful in 2013 and the first half of this year. There has been an increase in holdups recently, however.

In addition to the two robberies at the Manchester Rite Aid, since Aug. 18 there have been holdups at two Augusta Rite Aids, one at Community Pharmacy inside Goggins IGA in Randolph and another at the Spring Street Rite Aid in Gardiner.

Jesse Spencer, 31, of Randolph has been charged with the Gardiner robbery. Police have called Dominic J. Pomerleau, 21, of Augusta, a suspect in both the Augusta robberies. Nobody has been identified or charged in connection with the Community Pharmacy robbery.

Police attributed the reduction in robberies in 2013 and this year to increased enforcement, including the decision to begin prosecuting the robberies federally, and the prevalence of cheap heroin funneling into the area from out of state. It is unclear what is driving the recent trend back to pills and the accompanying robberies.

“We don’t have any information that there is a shortage of heroin in the area, which is usually what causes addicts to switch opiates,” Augusta Deputy Police Chief Jared Mills said last week.

Kennebec County District Attorney Maeghan Maloney speculated that word of heroin’s dangers may be spreading.

“I wonder if it has any connection to heroin being laced with fentanyl right now,” she said recently. “There have been some deaths from heroin use due to heroin laced with fentanyl.”

Hatch asked anyone with information about Saturday’s robbery to call the Kennebec County Sheriff’s Office at 623-3614.