If the arrest was recent
Start with the county jail
Someone who was just arrested in Indiana is almost always in a COUNTY JAIL run by the county sheriff, not in a state prison, so the IDOC offender search will not show them.
Indiana has 92 counties, each sheriff running its own jail, and there is no single statewide jail roster.
Many Indiana sheriffs publish an online jail/inmate roster (larger counties such as Marion County, Indianapolis, have their own lookup), but coverage and formats vary and the smallest jails may have nothing online.
The reliable paths for a recent arrest are the arresting county sheriff's jail roster, VINELink, or calling the jail's booking desk.
Indiana has 92 counties, each sheriff running its own jail and roster (some with no online search); there is no unified statewide county-jail search, so use VINELink or the arresting county sheriff.