Boston Police report they are looking for a guy they say has grabbed two women from behind and robbed a third.

Police say the most recent incident was yesterday afternoon when a woman had her buttocks touched by the guy twice, first at F and W. 8 streets and then again at F and Tudor streets as she was trying to get away. The suspect was described as a black guy, 5'6", between 16 and 20 in a black jacket with a fur-lined hood and riding a dark bike.

Police say a similar double attack happened around noon on Dec. 6 to a female jogger at Columbia Road and Mt. Vernon streets and at Dorchester Avenue and Sudan streets. That victim described an older guy - 25-30 - but he was also riding a bike, this time described as red.

Two days before that, around 8:30 a.m. a woman reported her handbag was snatched by a black guy on a red and black bike at the JFK/UMass T stop.