SPOKANE, Wash. -

For the fourth time in three days, Spokane police are investigating an armed robbery at a pharmacy.

The latest robbery happened around 1 p.m. at the Providence West Medical Building on West 5th Ave. Police say a white man in his mid 40's flashed a gun  before taking off with prescription drugs. They are now checking surveillance cameras and dusting for finger prints.

Detectives are also looking to see if this robbery is connected with another string of pharmacy robberies carried out by a female suspect.

Police say they have ample video surveillance and tips from the public to give them a pretty good idea who is committing these robberies. They believe an arrest will be made soon.

All the evidence collected in the last robberies points to a woman caught on video robbing an Albertson's in Spokane. She didn't use a weapon but in one case she handed the clerk a note demanding oxycodone with a threat that if she didn't get it she would jump the counter and take it herself.

"Somebody striking so often indicates that she is very desperate I would imagine," said Spokane Police Captain Joe Walker.

Police say in many cases like this, someone addicted to a drug, like oxycodone, losses their supplier, often to a drug bust and takes it on themselves to feed their habit.

"The video that we have right now is very good and again we've got a lot of tips coming in," said Walker.

The suspect is described as a female in her 20's, about 5'4" and weighing around 125 pounds.  This suspect made quite a few appearances on security cameras. Police believe they will make an arrest very soon.

Even with a lot of people calling in with tips police say it never hurts to have more information. Anyone can help by calling crime stoppers at 1-800-222-TIPS.