Watch The Exorcist III (1990) HD Full Movie Free on SolarMovie. Watch The Exorcist III (1990) online free. A police lieutenant uncovers more than he bargained for as his investigation of a series of murders,...A police lieutenant uncovers more than he bargained for as his investigation of a series of murders, which have all the hallmarks of the deceased Gemini serial killer, leads him to question the patients of a psychiatric ward.