Greenville police are now investigating a fire that heavily damaged a duplex early this morning. Greenville Fire-Rescue units were called to the duplex at 803 Colonial Avenue around 5:45 a.m. The fire heavily damaged the left unit of the duplex. Firefighters say fire was showing on the first floor of the vacant duplex when they arrived and no one was injured. The cause of the fire has been ruled undetermined pending further investigation, according to a fire department news release. Greenville police are now looking into the fire, and the fire department says it will be several days before any new details are released.