Indiana Code Title 5. State and Local Administration § 5-1-11-4

Sec. 4. (a) It shall be unlawful for any officer or body authorized by law to issue or sell bonds to enter into a contract or agreement prior to the award of such bonds with any person, limited liability company, firm, or corporation, directly or indirectly interested in bidding on or purchasing such bonds, for the furnishing of legal, engineering, or other technical services, or for the furnishing of printed bond forms or any other contract or agreement which will give to any person, firm, limited liability company, or corporation an advantage in bidding on or purchasing such bonds or controlling the sale thereof.  Any funds expended on account of any such contract or agreement shall be chargeable to the officer or officers authorizing or making such expenditure.

(b) It shall be unlawful for any officer or body authorized to issue or sell bonds to require the successful bidder therefor to pay for such bonds prior to the time that such bonds are delivered, or prior to the time that the successful bidder shall have had reasonable opportunity to examine such bonds and the proceedings had relative to the authorization, issuance and sale of the same.  Nothing in this chapter, however, shall prevent any county, township, city, town, school corporation or special taxing district from employing or contracting for legal, engineering or other technical services, prior to the sale of any such bonds, provided that such services are not to be supplied by or through a person, firm, limited liability company, or corporation directly or indirectly interested in bidding on or purchasing such bonds.