Police are asking for the public’s help after a string of iPad robberies across Brooklyn — and one in Manhattan — that investigators believe may all be connected.

Surveillance images released this week show three people, all dressed in black, including black bubble coats, going through a subway turnstile. Police say those images are from one of the most recent incidents and may help identify the group involved.

According to investigators, the robberies happened over several weeks in December and followed a similar pattern. In one of the earliest cases, police say a man walking out of an Apple store on Flatbush Avenue on Dec. 5 had an iPad taken directly from his hand. No injuries were reported.

Later in the month, on Dec. 22, police say a woman walking along State Street in Downtown Brooklyn had a bag containing an iPad taken from her. No serious injuries were reported.

Police say the most recent incidents happened on Dec. 28. In one case, a 17-year-old left a store on Flatbush Avenue and was followed onto an R train. After getting off at a stop in Brooklyn, police say the teen had a bag taken before the group ran off.

That same night, police say a woman in Manhattan was pushed to the ground and had a bag containing iPads stolen. She suffered minor injuries but was not hospitalized.

Investigators say most of the people targeted were not seriously hurt, but they are concerned about how quickly the robberies happened and how similar each case appears to be.

Police are urging anyone who recognizes something in the surveillance images — a face, clothing or another detail — to come forward.

Anyone with information is asked to contact the NYPD’s Crime Stoppers hotline at 1-800-577-TIPS (8477).