Indiana Code Title 34. Civil Law and Procedure § 34-24-4-10

Sec. 10. (a) Proof of participation in the illegal drug market in an action brought under this chapter (or IC 34-1-70 before its repeal) must be shown by clear and convincing evidence.  Unless otherwise provided in this chapter, other elements of an action brought under this chapter must be shown by a preponderance of the evidence.

(b) A person:

is estopped from denying participation in the illegal drug market.

(c) A conviction described in subsection (b) constitutes prima facie evidence of the person's participation in the illegal drug market during the two (2) years preceding the date of the act that was the basis for the conviction.

(d) Notwithstanding subsection (c), a person may not be prohibited from bringing an action under this chapter (or IC 34-1-70 before its repeal) against another person because the other person has not been convicted of a criminal drug offense.