Campbell County authorities today said they continue to investigate the cause of an early Christmas morning fatal fire – but that it does not appear to be in suspicious in nature.  The fire broke out around 12:30am Friday at 46 Spruce Lane.  When fire crews got there, they found the residence fully engulfed and were unable to get to the person inside.   Family members have identified the victim as 57-year-old Hazel “Susie” Callahan. Remains have been sent to the medical examiner.