A person is in hospital with life-threatening injuries after reports of an assault in Tillsonburg. Around 4:45 p.m. on Saturday, OPP, along with fire and emergency medical services, responded to a report of an assault in the area of Prospect Street. While there, crews were called to a structure fire, also on prospect street. There was an increased police presence in the area while officials investigated. A 41-year-old from Tillsonburg was arrested and charged with aggravated assault and arson. No details have been provided in terms of the type of assault, or the connection between the assault and the fire.