Police are looking for a man who attempted to rob a coffee shop Tuesday night in South Portland.

The robbery at the Aroma Joe’s at 443 Western Ave. is the eighth robbery in as many days in Greater Portland. Police in five communities are working together to investigate the string of armed robberies and are asking business owners and residents to stay vigilant.

The woman working at Aroma Joe’s was alone inside the drive-up coffee around 8:30 p.m. when a man walked up and knocked on the window with a handgun, the employee told News Center Maine (WCSH/WLBZ). She ran to the shop’s bathroom, where she used her Apple Watch to call police.

The robber fled on foot without getting any cash, police said.

Detective Sgt. Christopher Todd said police arrived at Aroma Joe’s within two minutes of the employee’s 911 call. The robber fled on foot in an unknown direction.

“Luckily, no one was hurt in this incident and the clerk’s quick thinking allowed police to arrive very quickly. At the very least they were able to stop any further violence from occurring,” Todd said.

The South Portland suspect is described as a white man, about 5 feet 7 inches tall, with a thin build. He was wearing a dark hooded sweatshirt with the lower half of his face covered.

The description is similar to that of the suspects in a string of previous robberies in the Greater Portland area.

On Tuesday, Westbrook police released surveillance video of a robbery that occurred at a Subway restaurant Monday night, in hopes someone will recognize the masked man responsible for the crime.

Hours before the seventh robbery, Portland police held a news conference to say they believe there is a connection between the first six robberies and to ask for the public’s help as they investigate the unusual cluster of potentially dangerous crimes.

The departments are pooling resources and detectives are asking the public to help by scouring private home or business surveillance systems that may have captured images of the robberies showing the suspect and any vehicle that may have been involved.

The robberies were reported in Portland, Westbrook, Falmouth and Cumberland starting March 20. No one has been hurt.

Police are urging store owners and citizens to remain vigilant, and warned against intervening in any ongoing crimes.

Scarborough police shared on Facebook a list of suggestions for businesses that could be targeted by a robber. Recommendations include installing a panic alarm and surveillance system, staying alert for suspicious vehicles and people, keeping small amounts of cash in the business, and making sure front windows are not cluttered with signs or posters.

If a business is robbed, police say employees should quickly and calmly hand over cash without fighting, take in as many details as possible to provide police, and call 911 as soon as it is safe to do so. All doors should also be locked as soon as possible to prevent the robber from re-entering the business. Police also suggested employers considering keeping at least two employees in the business at all times.

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