Authorities in Flagstaff are investigating a possible arson at a Walmart store, which will remain closed until further notice because of severe fire and water damage. Flagstaff police responded to the scene at the Walmart on East Huntington Drive around 3 a.m. Saturday and reported heavy smoke inside the store and the sprinkler system activated. Store employees told officers on the scene that a man was seen leaving sections of the store where the fire started. They provided Flagstaff police with a description of the possible suspect and what he was wearing. Police are asking anyone with information that may help identify the suspect in the investigation to contact either the department or the Silent Witness program.