Investigators are searching for the cause of a duplex fire in Davenport yesterday (Tuesday) that badly injured three people. Fire Chief Mark Frese says they found two children and a man in a second floor bedroom and got them out as fast as they could. Neighbors called 9-1-1 after hearing children screaming from the second floor. Frese says flames were coming out the front door when firefighters got arrived. Firefighters went inside right away, found all three people and got them out within six minutes.23-year-old Mike Stewart and his children, 6-year-old Amber and 4-year-old Daniel, are in critical condition at University Hospitals in Iowa City. The mother of the children was at work at the time of the fire. The father works a night shift and takes care of the children during the day.