Ind. Code § 28-7-5-20
The pawnbroker shall at the time of making a loan or purchase require the signature and right thumbprint of the pledger on all pawn tickets, bills of sale, or ledger cards retained by the licensee. If the person is unable to write, the person shall sign by mark. In such event, the pawnbroker shall record on the signature card such information as will enable the pawnbroker to identify the person in case of the loss of the ticket. If the person does not have a right thumb, any other existing finger may be used. However, a clear print must be obtained. A pawnbroker that maintains an electronic record of a thumbprint obtained under this section satisfies the record keeping requirement of this section if the electronic record is capable of being reproduced.
IC 28-7-5-20