The prosecution, which is seeking the death penalty for Woldt, one of two men who abducted, raped and killed Jacine Gielinski on April 29, 1997, will cross examine Dr. Jonathan Pincus, a Washington, D.C., neurologist, today.

Gielinski, a graduate of Littleton High School, was a student at the University of Colorado at Colorado Springs when she was abducted outside her boyfriend's apartment.

Woldt and his accomplice, Lucas Salmon, raped her, slashed at her throat with a steak knife and repeatedly stabbed her chest before suffocating her.

Pincus, who has interviewed between 150 and 200 convicted murderers, many of those on death row, said in most cases such violence is triggered by a combination of three factors: mental illness, physical and/or sexual abuse as a child and neurological damage.

All three exist in Woldt, he said. Woldt suffers severe obsessive-compulsive disorder, has scars on his back and at least two police reports proving childhood abuse and suffers from a lesion at the center of his brain that affected his judgment.

Medical images of Woldt's brain in the fall of 1997 indicated that Woldt's lesion was bleeding. In addition, reflex and strength tests conducted at the time by doctors showed a right-side weakness that Woldt no longer exhibits, Pincus said.

"What happens? If this had not been George Woldt, if he did not have obsessive-compulsive disorder, if he had not been abused like George Woldt, maybe nothing."

The scars and Woldt's responses to questions posed by Pincus in July would indicate that Woldt was physically abused by his father, who couldn't tolerate his obsessive-compulsive behavior and didn't believe he was his son. At the same time, his mother, who suffered from delusions, was no comfort and even came at him with a knife, Pincus said.

Woldt, who threw up during Tuesday's lunch break and received pain killers for a migraine during the afternoon session, is obsessed with germs and washes frequently, must smell everything he touches and cannot tolerate being touched himself, Pincus testified.

In addition, Woldt closes his eyes, clenches his fists and strikes his knees when he seems unable to express himself adequately, signs of another brain dysfunction.

"Could he be feigning?" asked defense attorney Terri Brake.

"Absolutely not," Pincus responded.

"This behavior has been consistent for years."

Although Lucas Salmon has been sentenced to life in prison, prosecutors contend Woldt was the mastermind behind the crime and deserves death by lethal injection. Woldt's sentencing hearing is expected to last two weeks.