In 2017 allegations were made against Hillier for violating the internal conduct policies of Tay Valley Township and the Occupational Health and Safety Act. Following a three-month investigation Hillier was found to have harassed municipal staff in Tay Valley. The township investigation wrote that Hillier “unfairly called into question the competence and proficiency of Township staff and undermined their integrity.” A letter from the township Chief Administrative Officer said there was a pattern of criticism and that the MPP had been “cautioned” about this “type of behaviour” in March. The letter stated. “Much of the information upon which you rely for your criticisms is inaccurate and the commentary about staff is disparaging. The impact of this behaviour is made even more harmful by the position and authority that you hold as MPP.”