According to court records, Sullivan was diagnosed in 2001 as a paranoid schizophrenic and has a history of menacing females.
When he was booked into the Clark County Jail on Thursday, Sullivan reportedly told a corrections officer, "I should have stayed home with my stuffed animals instead of doing what I did. This is all evil stuff that I've done. This is too much."
Sullivan's criminal record in Clark County includes a 1999 conviction for fourth-degree assault with sexual motivation.
In 2001, he attempted to kidnap a 14-year-old girl from Naydenov Gymnastics Center. After a mental health evaluation, he pleaded guilty to unlawful imprisonment with sexual motivation.
While on community supervision for that offense, he was watching a 15-year-old girl run around the track at Mountain View High School on June 14, 2003. The girl became scared and ran across the football field toward her home, according to court documents. Sullivan chased her but didn't catch her. The girl later identified Sullivan when a Vancouver police officer showed her photographs of registered sex offenders.
His corrections officer wrote on July 1, 2003 that Sullivan "has had difficulty adjusting to supervision, in part, because of his mental health disabilities." The officer said that the Mountain View incident "encompasses the same behavior which led to his previous convictions."
The officer did note, however, that Sullivan had a stable residence and had begun mental health and sex offender treatment.
Sullivan lives with his parents in the Roads End neighborhood, about one mile northwest of the murder scene.
His father reportedly told a corrections officer that his son takes Risperdal, an antipsychotic, and Prozac and receives mental health treatment. He said his son hasn't been able to keep a job since high school. His parents were not available for comment Friday.
"One thing we don't have here is a lot of guessing to do," said Police Chief Brian Martinek during a press conference Friday morning. "Except the craziness of why someone would do this to an innocent young girl."
There's no evidence Svidersky knew her attacker, Martinek said.
"We believe this was a random incident," he said.
Asked if there was any precedent for such a crime, Martinek said senseless violence occurs all over the country.
"It's unfortunately part of being a big city," he said. "We don't have any magic wall around us here."
