Indiana Code Title 34. Civil Law and Procedure § 34-13-5-2

Sec. 2. (a) Plaintiffs in a public lawsuit may sue in their capacity either as citizens or taxpayers of the municipal corporation.

(b) A public lawsuit described in subsection (a) is a class suit (whether captioned as such or not), subject to the rights of intervention, the addition of parties, and the addition of other representatives of the same class, as is provided by law in other civil actions. Special appearances may be made in situations permitted by applicable law.