Authorities are still investigating what caused a fire at a house in Mosinee Tuesday night. The fire was reported around 8:30 p.m. at a house on the 800-block of 9th Street in Mosinee. Deputy Chief Adam Grahn said there were people in the home at the time of the fire. They made it out safely. Last night at approximately 8:30pm the Mosinee Fire District along with its auto aid (Kronenwetter, SAFER and Riverside) were paged to a structure fire in the city of Mosinee. With the help of the Mosinee PD and the homeowner the fire was knocked down until 78 Engine 1 arrived on scene to extinguish the remaining fire, overhaul and investigate. Due to Mosinee's Engine 1, Engine 3 and Engine 4 along with Rescue 1 and Med 1's quick response they were able to control the scene quickly cancelling our auto aid.