Sacramento fire crews are trying to extinguish a house fire that spread to at least one other home. LiveCopter 3 spotted a large black plume of smoke coming from a home along the 2100 block of Bell Avenue near McClellan Park. The Sacramento Fire Department said the fire has spread to both units in the duplex. It is unknown what caused the fire. This is a developing story. Stay with KCRA 3 for the latest.