their father. Others who testified for the defense told of how Gacy was a good and generous man, who helped those in need and always had a smile on his face. Lillie Grexa took the stand and told of how wonderful a neighbor he was. However, Mrs. Grexa did say something that would prove damaging to Gacys case. She refused to say that he was crazy, instead she said she believed Gacy to be a "very brilliant man." That statement would conflict with the defense's story that he was unable to control his actions and was insane.

The defense then called Thomas Eliseo, a psychologist who interviewed Gacy before the trial. He found Gacy to be extremely intelligent, yet believed that he suffered from borderline schizophrenia. Other medical expertsthat testified on behalf of the defense gave similar testimony stating that Gacy was schizophrenic, suffered from multiple personality disorder or had antisocial behaviour. They further stated that Gacys mental disorder impaired his ability to understand the magnitude of his criminal acts. In conclusion, they all found him to have been insane during the times he committed murder. After the testimony of the medical experts, the defense rested its case.

Both sides emotionally argued their cases to the jury that sat before them. Each side recalled previous witnesses and experts who had testified. The prosecution reminded the jury of the heinous crimes committed by Gacy, talked of his manipulative behavior, his rape and torture of the victims and how his crimes were premeditated and planned. The defense insisted that