MURDER.

(a) In this section:

(1) "Adequate cause" means cause that would commonly produce a degree of anger, rage, resentment, or terror in a person of ordinary temper, sufficient to render the mind incapable of cool reflection.

(2) "Sudden passion" means passion directly caused by and arising out of provocation by the individual killed or another acting with the person killed which passion arises at the time of the offense and is not solely the result of former provocation.

(b) A person commits an offense if the person:

(1) intentionally or knowingly causes the death of an individual;

(2) intends to cause serious bodily injury and commits an act clearly dangerous to human life that causes the death of an individual;

(3) commits or attempts to commit a felony, other than manslaughter, and in the course of and in furtherance of the commission or attempt, or in immediate flight from the commission or attempt, the person commits or attempts to commit an act clearly dangerous to human life that causes the death of an individual; or

(4) knowingly manufactures or delivers a controlled substance included in Penalty Group 1-B under Section 481.1022, Health and Safety Code, in violation of Section 481.1123, Health and Safety Code, and an individual dies as a result of injecting, ingesting, inhaling, or introducing into the individual's body any amount of the controlled substance manufactured or delivered by the actor, regardless of whether the controlled substance was used by itself or with another substance, including a drug, adulterant, or dilutant.

(c) Except as provided by Subsection (d), an offense under this section is a felony of the first degree.

(d) At the punishment stage of a trial, the defendant may raise the issue as to whether he caused the death under the immediate influence of sudden passion arising from an adequate cause. If the defendant proves the issue in the affirmative by a preponderance of the evidence, the offense is a felony of the second degree.

(e) It is a defense to prosecution under Subsection (b)(4) that the actor's conduct in manufacturing or delivering the controlled substance was authorized under Chapter 481, Health and Safety Code, or other state or federal law.