Testimony in the death penalty trial of convicted triple murderer Joseph Michael Nissensohn on Thursday focused on his mental disorders, brain damage from heavy drug use and the risk of him hurting others if sentenced to life in prison without parole.
An El Dorado County jury is expected to decide Nissensohn’s sentence next week after two days of testimony.
Nissensohn, 62, faces the death penalty for murdering three California teens: Kathy Graves of South Lake Tahoe in 1989 and Tammy Jarschke and Tanya Jones, both of Seaside, in 1981. The three girls ranged in age from 13 to 15 when killed.
Nissensohn previously was convicted of second-degree murder for the 1989 killing of a Washington state woman.
Pointing to brain scans taken last month at University of California, Davis, Dr. Douglas Taylor said Nissensohn’s brain is two-thirds the size of a normal brain and spotted with dead tissue from heavy intravenous cocaine use in his 20s and 30s.
Taylor, a medical doctor specializing in psychiatry and substance abuse issues, was brought in to testify by the defense. He showed the jury what he described as images of “extremely dramatic” drug-induced brain damage visible to the naked eye.
Some of that damage is in Nissensohn’s frontal lobes, a part of the brain “that makes people human” and is involved in empathy, judgment, decision-making and controlling sexual and violent impulses, Taylor said.
Taylor testified that Nissensohn’s brain damage likely predated or coincided with the four known murders he committed and that, without the damage, Nissensohn would have been less likely to commit them.
Deputy district attorney Dale Gomes challenged the assertions as speculation in cross-examination of Taylor.
Testimony also touched on Nissensohn’s poor health as a factor in his risk of hurting others in prison. Taylor testified that Nissensohn has degenerative joint disease in his fingers, knees and neck, heart conditions and hepatitis C.
Nissensohn’s defense also called on James Esten, a corrections consultant and former instructor, supervisor and inmate appeals examiner for California Department of Corrections.
Esten testified that Nissensohn would be housed in a level four prison — the most secure facility — and that in his opinion Nissensohn could be housed without threat to other inmates or prison staff.
“The defendant has never had an inmate-manufactured weapon, never assaulted staff,” Esten said.
Prosecutors seeking the death penalty argued Nissensohn has a history of preying upon people who are weaker than he is, both inside and outside of prison, and would continue to pose a risk.
Nissensohn grabbed and choked a young man in the El Dorado County Jail two-and-a-half years ago, prosecutors said.
While serving time for second-degree murder in Washington, Nissensohn was caught corresponding with young women, asking them to engage in incestuous behaviors and other sexual activities, prosecutors said, arguing Nissensohn would continue to pose a danger to those in prison weaker than he is and those outside prison that he could correspond with.