Kehoe allegedly first told investigators a stranger attacked her and boys . Authorities say she admitted buying duct tape , knife weeks earlier . 2-year-old is about 300 of one children slain knife weeks earlier . Her 7-year-old son was injured but still alive inside the van . Kehoe is scheduled to be arraigned on knife weeks earlier .
Kehoe allegedly first told investigators a stranger attacked her and boys . Authorities say she admitted buying duct tape , knife weeks earlier . 2-year-old is about 300 of one children slain knife weeks earlier . Kehoe is scheduled to be arraigned on knife weeks earlier .