Janesville firefighters are investigating a residential blaze on the city’s northeast side.  Officials say firefighters were called to a single family home in the 14-hundred block of Greenwich Lane just before 5:00 p.m. Thursday.  While in route, firefighters learned the occupants had escaped.  Firefighters arrived to find flames showing form the rear of the one story home.  Two dogs and a cat were rescued.  One cat is still missing.  Damage is estimated around 80-thousand dollars.  The Red Cross is assisting four-adults and two-children.