Why Jeffrey Dahmer Was Declared Sane In His Murder Trial

Despite the fact that serial killer Jeffrey Dahmer murdered multiple people and even ate some of them, he was declared legally sane. 

Netflix’s “Conversations with a Killer: The Jeffrey Dahmer Tapes” reflects on Dahmer’s trial and its focus on his sanity — or rather, his possible insanity. Dahmer had killed 17 men and boys, many of whom were Black and gay, between 1978 and 1991. He had sex with all of them after they died and kept some of their skulls and other body parts. Dahmer also had a habit of drugging and sexually assaulting men.

During his 1992 murder trial, Dahmer’s defense — as well as his father — were hoping that Dahmer would be found legally insane. Lt. Kenneth Meuler of the Milwaukee Police Department’s Homicide Division noted in the docuseries that Dahmer’s dad Lionel Dahmer hoped that “there’s some understanding that he did this because of a mental disease.”

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Dahmer pleaded not guilty by reason of insanity and the defense was tasked with proving their case. Gerald Boyle, lead defense attorney for Dahmer, promised the jury that he would prove that Dahmer was “sick” and not “evil.” 

“My duty and my goal were to prove that he was insane during the commission of these offenses,” Boyle told the producers of “Conversations with a Killer.” “That when he killed somebody he was suffering from mental illness.”

He added that to be found insane, a person must “lack the capacity” to understand the difference between right and wrong or “they are unable to control their conduct to the requirements of the law.”

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Dr. Carl Wahlstrom, a forensic psychiatrist who testified for the defense, told the jury that Dahmer had schizotypal and borderline personality disorder elements because he experienced “frantic attempts to avoid real or imagined abandonment and in this case, it’s the most extreme example of those frantic attempts.”

He also called Dahmer’s attempt to keep the skulls and bones of his victims a “delusion,” as he hoped to gain “special powers” from them.

But Dr. Park Dietz, a forensic psychiatrist for the prosecution, told the jury that at the time of the murders “he did have the capacity” to control himself.

“There was no force pushing him to kill,” he testified. “There was merely a desire to spend more time with the victim. If the victim had agreed voluntarily to stay with him, he would not have done the killing. That’s an indication that he could control his behavior.”

The prosecution's expert said in the docuseries that Dahmer “said he knew it was wrong at the time” of the killings, so therefore he knew the difference between right and wrong. In fact, nearly all the psychiatrists agreed that he knew it was wrong but there was disagreement over whether or not he could control himself.

Dietz added that Dahmer took preventative measures for each one of the killings as to not get caught, including putting in fake security cameras to deter people from breaking into his home and disposing of evidence.

“In order to kill, he had to overcome his inhibition against it by getting drunk,” he said.

And even though Dahmer’s acts seem on par with insanity, they don’t meet the legal definition of it. He was found both sane and guilty at the end of the two-week trial.

''Jeffrey Dahmer knew exactly what he was doing," George Palermo, another forensic psychiatrist, testified in the trial, the Chicago Tribune reported in 1992. "He took precautions. He knew the consequences of his actions. But he did not want to stop."

He added, ''Nobody can deny that Jeffrey Dahmer is a sick person. [But] he is not psychotic. He was legally sane at the time of the offenses.''