Boston Police are investigating a string of cash register robberies at four Boston stores in different neighborhoods over the past week that may be connected.

In each robbery, police said the thief pretended to buy something before grabbing the cash register when the employee opened it and fleeing with the cash inside. Police didn't say how much cash was stolen in each robbery, but they did say that the suspect did not show any weapons.

Police are unsure how many suspects may be involved or if it is just one person.

The suspect was described as wearing black pants, with a black surgical mask, as well as a black puffer jacket with a hood.

The cash register robberies happened at stores on River Street and Fairmount Avenue in Hyde Park, Parker Street in Roxbury and Heath Street in Jamaica Plain.

Anyone with information is asked to call Boston Police at 1-800-494-TIPS. Officers also ask that anyone with videos or photos submit them online here.

In another incident this week in Boston, police are looking for a group of people who shoplifted the Lululemon store on Newbury Street on October 13. Surveillance video captured three people fleeing the store shortly after 7 p.m. with armfuls of clothing while a fourth person ran after them. They were last seen leaving the area in a dark-colored sedan and heading outbound on Newbury Street.

According to police, the stolen merchandise was worth $6,140.