Authorities in Lexington, Missouri, are investigating a massive house fire early Wednesday that may be linked to multiple arson fires set earlier this week.Officials with Lexington Fire and Rescue said emergency crews were working an arson fire on MO-224 Highway just west of Lexington. Authorities said witnesses reported seeing a vehicle leave the scene that matched the description of a vehicle involved in the multiple arson fires set in the Polo area Tuesday. However, while that vehicle was described as a black Dodge Caliber or similar vehicle, authorities later updated the description to say the vehicle seen at the Lexington fire was a black truck.No injuries were reported in the Lexington blaze. The structure is a total loss.The Missouri State Fire Marshal's Office was called in to investigate Tuesday's fires. Police said three homes in Caldwell County were involved, and one woman was killed. The Caldwell County Sheriff's Office said it received the first report of a fire at about 8:30 a.m. near Route D and Colt Drive in rural Polo. The sheriff's office said an older woman died in the fire.Investigators said that over the next two hours, deputies and firefighters were called to two other house fires along Route D. Both of those houses were vacant.Authorities said they believe the fires are related and arson is suspected.The sheriff's office said a dark, four-door passenger car, possibly a black Dodge Caliber, was spotted near each fire.Authorities in Lexington ask that residents be on the lookout, and report any and all suspicious activity. Anyone with information in the investigation is asked to call the Caldwell County Sheriff's Office at 816-586-2681.