SOUTH SHORE — Neighbors of Rainbow Beach are on guard after two recent sexual assaults in the area, which police say were likely committed by the same person. In both instances, a man attacked two women from behind and groped them this month near Rainbow Beach, according to a community alert issued by the Police Department this week. The first attack took place the morning of June 13, when the man threw a woman to the ground and assaulted her in the 3100 block of East 79th Street, police said.