(1) As used in this section, the term “mental retardation” means significantly subaverage general intellectual functioning existing concurrently with deficits in adaptive behavior and manifested during the period from conception to age 18. The term “significantly subaverage general intellectual functioning,” for the purpose of this section, means performance that is two or more standard deviations from the mean score on a standardized intelligence test specified in the rules of the Agency for Persons with Disabilities. The term “adaptive behavior,” for the purpose of this definition, means the effectiveness or degree with which an individual meets the standards of personal independence and social responsibility expected of his or her age, cultural group, and community. The Agency for Persons with Disabilities shall adopt rules to specify the standardized intelligence tests as provided in this subsection.
(2) A sentence of death may not be imposed upon a defendant convicted of a capital felony if it is determined in accordance with this section that the defendant has mental retardation.
(3) A defendant charged with a capital felony who intends to raise mental retardation as a bar to the death sentence must give notice of such intention in accordance with the rules of court governing notices of intent to offer expert testimony regarding mental health mitigation during the penalty phase of a capital trial.
(4) After a defendant who has given notice of his or her intention to raise mental retardation as a bar to the death sentence is convicted of a capital felony and an advisory jury has returned a recommended sentence of death, the defendant may file a motion to determine whether the defendant has mental retardation. Upon receipt of the motion, the court shall appoint two experts in the field of mental retardation who shall evaluate the defendant and report their findings to the court and all interested parties prior to the final sentencing hearing. Notwithstanding s. 921.141 or s. 921.142, the final sentencing hearing shall be held without a jury. At the final sentencing hearing, the court shall consider the findings of the court-appointed experts and consider the findings of any other expert which is offered by the state or the defense on the issue of whether the defendant has mental retardation. If the court finds, by clear and convincing evidence, that the defendant has mental retardation as defined in subsection (1), the court may not impose a sentence of death and shall enter a written order that sets forth with specificity the findings in support of the determination.
(5) If a defendant waives his or her right to a recommended sentence by an advisory jury following a plea of guilt or nolo contendere to a capital felony and adjudication of guilt by the court, or following a jury finding of guilt of a capital felony, upon acceptance of the waiver by the court, a defendant who has given notice as required in subsection (3) may file a motion for a determination of mental retardation. Upon granting the motion, the court shall proceed as provided in subsection (4).
(6) If, following a recommendation by an advisory jury that the defendant be sentenced to life imprisonment, the state intends to request the court to order that the defendant be sentenced to death, the state must inform the defendant of such request if the defendant has notified the court of his or her intent to raise mental retardation as a bar to the death sentence. After receipt of the notice from the state, the defendant may file a motion requesting a determination by the court of whether the defendant has mental retardation. Upon granting the motion, the court shall proceed as provided in subsection (4).
(7) The state may appeal, pursuant to s. 924.07, a determination of mental retardation made under subsection (4).
(8) This section does not apply to a defendant who was sentenced to death prior to the effective date of this act.