Section 943.02 - Arson of buildings; damage of property by explosives(1) Whoever does any of the following is guilty of a Class C felony: (a) By means of fire, intentionally damages any building of another without the other's consent; or(b) By means of fire, intentionally damages any building with intent to defraud an insurer of that building; or(c) By means of explosives, intentionally damages any property of another without the other's consent.(2) In this section "building of another" means a building in which a person other than the actor has a legal or equitable interest which the actor has no right to defeat or impair, even though the actor may also have a legal or equitable interest in the building. Proof that the actor recovered or attempted to recover on a policy of insurance by reason of the fire is relevant but not essential to establish the actor's intent to defraud the insurer.1977 c. 173; 1993 a. 486; 2001 a. 109. A mortgagee's interest is protected under sub. (1) (a); evidence of fire insurance was admissible to prove a violation of sub. (1) (a). State v. Phillips, 99 Wis. 2d 46, 298 N.W.2d 239 (Ct. App. 1980). Criminal damage to property under s. 943.01 is a lesser-included offense of arson. State v. Thompson, 146 Wis. 2d 554, 431 N.W.2d 716 (Ct. App. 1988). For purposes of this section, an explosive is any chemical compound, mixture, or device, the primary purpose for which is to function by explosion. An explosion is a substantially instantaneous release of both gas and heat. State v. Brulport, 202 Wis. 2d 505, 551 N.W.2d 824 (Ct. App. 1996), 95-1687.