Beloit fire officials are investigating the cause of an early morning blaze on the city’s east side.  Firefighters were called out a little before 3:00 a.m. Thursday for a residential fire in the 1700 block of Hemlock Street.  Authorities say smoke and flames were showing when firefighters arrived.  Residents of the home had already escaped.  No one was reported injured.  The building is considered a total loss.