Wheaton police are investigating an aggravated arson after finding a Molotov cocktail at the scene of a fire in the west suburb. Residents heard explosions about 10 p.m. Monday in the 1100 and 1200 block of South Washington Street, according to Wheaton police. When emergency crews arrived, they found fire and damaged property at a home in the area. One of the residents was able to put out the fire, police said. Investigators found the remnants of what appeared to be a Molotov cocktail that was used to start the fire.