INDIAN RIVER COUNTY — Indian River Fire Rescue is investigating a house fire just outside the Fellsmere city limits in which a 75-year-old woman died.Fellsmere Police Chief Scott Melanson confirmed the fatality, stating he believed the emergency call was received between 11 p.m. Friday and 12:30 a.m. Saturday. The Fellsmere police were at the scene, but the investigation of the home on the 100th block of 129th Lane is being conducted by Indian River Fire Rescue.The identity of the woman has not been released.