Utah police say a mother is the suspect in the killing of her 4-year-old daughter.  West Valley City police said in a news release Tuesday that the woman knocked on her neighbor’s door in a Salt Lake City suburb early Tuesday morning and told them she had killed her daughter. Officers went to the house and found the woman waiting on the porch and the dead child in the basement of her home. The woman’s 6-year-old son was found unharmed sleeping in the home. Police aren’t releasing the mother’s name, but say she was taken into custody and is the suspect.