ABC News November 4, 2024

'Satan killed the girls,' Delphi suspect said, according to neuropsychologist

WATCH: Witnesses reveal new details about police investigation into Delphi teen murders

Delphi, Indiana, double murder suspect Richard Allen made up stories while in a psychotic state, and claimed that "Satan killed the girls," according to a neuropsychologist who testified for the defense.

Allen was arrested in the fall of 2022 for the murders of teens Libby German and Abby Williams. By the spring of 2023, he began confessing to the murders and his behavior took a turn, according to testimony from corrections officers and a psychologist.

Allen's strange behavior included hitting his head on the wall, washing his face in the toilet, refusing food, eating paper, smearing feces in his cell and putting feces on his face for two hours, according to testimony from corrections officers.

MORE: Delphi murder suspect spent 13 months in solitary confinement, which damages mental health: Defense

Neuropsychologist Polly Westcott, who was hired by the defense in May 2023, testified Monday that Allen had depression and anxiety when he arrived in jail.

Westcott said she diagnosed Allen with dependent personality disorder, noting he was particularly dependent on his wife, Kathy.

Indiana State Police via AP, FILE
This undated image provided by Indiana State Police shows Richard Matthew Allen.
MORE: Delphi murder trial: Libby's blood was likely mixed with her tears, expert says

When Allen was cut off from his wife, Westcott said, his depression became more pronounced and escalated into psychosis. Westcott said Allen experienced hallucinations, psychosis and suicidal ideation.

"He fell apart," she said.

WRTV
Suspect Richard Allen is escorted from Carroll County Courthouse, Nov. 22, 2022, in Delphi, Indiana.
MORE: 'I did it': Delphi murder suspect's alleged phone confessions to wife played in court

Allen spent 13 months in solitary confinement, which Westcott said "can change brain chemistry."

Westcott said other prisoners would yell at Allen, calling him a "baby killer."

Li Buszka
Defendant Richard Allen with defense attorney Andrew Baldwin, Nov. 4, 2024.
MORE: Delphi murder suspect's alleged jail confessions revealed in court

She said Allen had no window, slept erratically and quickly lost weight.

"Your brain can’t tell what’s real,” she said. "It’s like being in a fun house. You don’t know what’s reality and what’s not.”

Allen is accused of killing Abby and Libby on a hiking trail in February 2017. He's pleaded not guilty to murder.

Courtesy Anna Williams
An undated handout photo shows Anna Williams with her daughter, Abby Williams, who was murdered in Delphi, Ind., in Feb. 2017.
Courtesy Becky Patty
An undated handout photo shows Libby German of Delphi, Ind., who was murdered in Feb. 2017.

Allen allegedly made multiple confessions to his wife, corrections officers and a psychologist while in jail, according to witnesses who testified for the state last week.

According to one corrections officer, on April 23, 2023, Allen said, "I killed Abby & Libby. My wife wasn't involved. I want to confess."

Three days later, Allen said, "Can I talk? Can you listen I killed Abby & Libby? How do I prove I'm insane?" according to the officer.

MORE: Delphi suspect went to police 3 days after the murders, but he 'fell in the cracks' for years: Sheriff

Psychologist Monica Wala testified that, in one of Allen's confessions to her, Allen told her he ordered the girls "down the hill" and intended to rape them. But then he saw something -- either a person or a van -- and was startled, Wala said. Allen told her he ordered the girls across the creek, slit their throats and covered their bodies with branches, according to Wala.

During cross-examination Monday, prosecutor Stacy Diener pressed Westcott about her claims that Allen made up stories while in a psychotic state. Diener asked, "Is everything a person says when in a psychotic state distorted due to their psychosis?"

Westcott responded, "Most of what a person says or perceives while in a psychotic state is not consistent with the world others perceive around them."

"But they could say things that are accurate?” Diener asked. Westcott responded, "Yes."