'Canal killer' trial: Miller 'walled off' experiences of childhood abuse, expert says

The childhood abuse experienced by Bryan Miller, accused of killing two young women in Phoenix 30 years ago, was so extreme that it fractured his consciousness in two, an expert witness testified Tuesday.

Forensic psychologist Dr. Mark Cunningham has spent days on the stand in the double murder trial detailing the childhood abuse Miller and others say he endured at the hands of his mother, who died in 2010.

Cunningham testified Tuesday that this chronic trauma had caused Miller to begin dissociating as a child, "walling off" his experiences into another state of consciousness, one his ordinary self had little or no awareness of.

“It’s functioning on its own," Cunningham said, of this second state. "It’s like an encapsulated tumor."

Miller has pleaded not guilty for reasons of insanity to murdering and attempting to sexually assault Angela Brosso on the eve of her 22nd birthday in November 1992, and Melanie Bernas, a high school student, in September 1993.

Both women died from a forceful stab wound to the back and were mutilated after death. They are believed to have been attacked as they cycled along Phoenix canals, and the case became known as the "canal killings." It went unsolved for decades until a DNA breakthrough led to Miller's arrest in 2015.

'Canal killings':A Phoenix man goes to trial 30 years after 2 women died

His insanity defense rests on several diagnoses, including autism spectrum disorder and dissociative disorder, that his attorneys say mean he could not understand his actions at the time of the murders.

The court has heard extensive evidence about Miller's experiences with his mother. Cunningham said Miller had been the victim of "sadistic" abuse, neglected both emotionally and physically, and repeatedly exposed to inappropriate sexual experiences, such as his mother watching softcore porn or violently erotic films while he was around.

Cunningham described Miller's consciousness as having split into a "normal state" and a "trauma state," where he stored all the experiences he could not cope with as a child.

“Those are invariably traumatic and anxiety-provoking and typically full of fear and rage and humiliation and shame and all kinds of feelings and experiences that are beyond the ability to be contained in a cohesive sense of self," he said.

The two states have limited awareness of one another, Cunningham said.

He said Miller's numerous other diagnoses — autism spectrum disorder, PTSD, anxiety and poor emotional modulation among them — had left him with scant resources to deal with trauma, making him even more vulnerable to dissociation.

Cunningham gave several examples of what he labeled "perverse sexuality" in Miller's mother, Ellen, and said she failed to observe normal sexual boundaries around her son. He pointed to evidence that she had exposed Miller to violent pornography, used sexually vulgar and threatening language with him, and masturbated in front of him, according to a former neighbor who contradicted this statement in a separate interview.

Miller's dysfunctional relationship with his mother had fused the concepts of eroticism and aggression in his early childhood, Cunningham said. The fusion was "critically important" to his analysis of Miller.

"In sexual homicides, there is nearly invariably a developmental history where a fusion of eroticism and violence has occurred," he said. "That is near universal in sexual homicides.”

His testimony continues on Monday.

This article originally appeared on Arizona Republic: 'Canal killer' trial: Bryan Miller 'walled off' trauma, expert says