A Lewiston woman was fatally stabbed in front of her two young children Sunday morning on the sidewalk outside a downtown laundromat, Maine State Police said. One of several bystanders who witnessed the attack tackled the man who stabbed Kimberly Dobbie, holding him until Lewiston police arrived, according to Steve McCausland, spokesman for the Maine Department of Public Safety. Dobbie, 48, had just started a load of laundry at Rancourt’s Laundromat on Sabattus Street and stepped outside with her children, 6 and 8 years old, when she was attacked just before 11 a.m. McCausland said Dobbie and her assailant knew one another, but he did not have any additional details about their relationship, or the confrontation outside the laundromat. The suspect, who had not been charged by Sunday evening, was hospitalized after reporting chest pains, McCausland said. Dobbie was taken to Central Maine Medical Center and died there early Sunday afternoon.