Indiana Code Title 3. Elections § 3-13-5-2

Sec. 2. (a) The state chairman of the political party that elected or selected the person who held the vacated seat shall set the place, date, and time of a caucus meeting.  The chairman shall send a notice, by first class mail, of the purpose, place, date, and time of the meeting to all precinct committeemen in the caucus at least ten (10) days before the meeting.

(b) If a vacancy in a legislative office exists because of the death of the legislator, the state chairman may not send the notice required by subsection (a) until the state chairman receives notice of the death from the secretary of state under IC 5-8-6.