(a) A defendant may not be convicted of an offense under Chapter 481, Health and Safety Code, on the testimony of a person who is not a licensed peace officer or a special investigator but who is acting covertly on behalf of a law enforcement agency or under the color of law enforcement unless the testimony is corroborated by other evidence tending to connect the defendant with the offense committed.
(b) Corroboration is not sufficient for the purposes of this article if the corroboration only shows the commission of the offense.
(c) In this article, "peace officer" means a person listed in Article 2A.001, and "special investigator" means a person listed in Article 2A.002.