The Texas Penal Code defines "element of offense" as: "(A) the forbidden conduct; (B) the required culpability; (C) any required result; (D) the negation of any exception to the offense." Tex. Penal Code Ann. 1.07(22) (West 1994). A failure to act is not an offense unless a defendant has a statutory duty to act. See Billingslea v. State, 780 S.W.2d 271, 276 (Tex. Crim. App. 1989); Sabine Consol., Inc. v. State, 816 S.W.2d 784, 787 (Tex. App.--Austin 1991, pet. ref'd).