WASHINGTON PARK, Ill. (AP) – Police in southwestern Illinois are investigating as a homicide an 84-year-old man’s death from a fire that began in his car.

Howard Brown died early Sunday after the fire sparked a gas tank explosion and then spread to his home.

Washington Park Police Chief Tony Tomlinson tells the St. Louis Post-Dispatch that investigators suspect Brown was killed by someone trying to collect a drug debt from a 31-year-old woman who occasionally stayed at his home. The FBI and Illinois State Police are assisting.

Brown’s garage was set on fire several weeks earlier, with a threatening note addressed to someone else taped to his car.

The police chief said that Brown’s kind nature had previously made him vulnerable to being victimized. He was an Army veteran and father of six.