Ind. Code § 29-1-10-5

Sec. 5. In any action or proceeding brought by the personal representative in such representative capacity, it shall not be necessary for him to make profert of his letters, nor shall his right to sue as such personal representative be questioned, unless the opposite party shall file a plea denying such right, with his affidavit to the truth thereof thereunto attached, in which case a copy of the letters issued to such personal representative, duly authenticated, shall be all the evidence necessary to establish such right.