A fire tore through an Omaha home early Wednesday morning, causing extensive damage.Omaha fire investigators said firefighters saw heavy smoke and flames while approaching the house near Fontenelle Boulevard and Bedford Avenue. They attacked the fire shortly after 4 a.m. and said it took about 10 minutes to extinguish.Officials said it didn't appear anyone was home at the time, but they weren't sure whether the house was vacant. There is extensive fire, smoke and water damage throughout the house.The cause of the fire remains under investigation.