The Madison Police Department has blocked off a portion of Highland Drive while they investigate a house fire they believe to be suspicious. The area blocked off is between Cherry Road and Spring Water Drive. Crews arrived to the house in the 800 block of Highland Drive around 1:15 a.m. They found a two-story house fully-engulfed in flames. It took firefighters roughly an hour to get the flames under control. Someone in the area told us something inside the house exploded before crews arrive, which seemed to be confirmed by the glass seen in the roadway.