Officers responded in West Terre Haute on Tuesday along with Vigo County sheriff's deputies and FBI agents.
Anthony Tillotson, 28, faces preliminary charges of creating a destructive device.
An IU student was arrested Wednesday under suspicion of manufacturing a bomb in his Bloomington apartment.
Monroe County Public Library received a bomb threat earlier today. It has now been reopened.
Private Brett Spencer was killed Friday after stepping on a bomb in Afghanistan.