Lone Wolf Killers: Unabomber's Brother Sees Isolation, Mental Illness as Key to Tucson Tragedy

David Kaczynski urges effort to understand what led shooter down deadly path.

ByMatthew Mosk and Brian Ross
January 10, 2011, 2:52 PM

Jan. 11, 2011 — -- In the aftermath of the tragic shooting in Tucson this week, there are lessons for preventing another mass casualty attack.

That's what the brother of Unabomber Ted Kaczynski told ABC News Monday night, as he digested descriptions of alleged shooter Jared Lee Loughner's behavior that carried echoes of his own experience.

"We can't undo the crime," David Kaczynski said. "What we can do is try to understand how and why it occurred. And maybe look for ways we could prevent it."

The alleged shooter's growing isolation and erratic behavior, as detailed in news accounts, are familiar as hallmarks of a "lone wolf," a personality type that has the potential to be lethal. But David Kaczynski believes the suspect in the Tucson shooting also carries many of the same symptoms of schizophrenia that his brother exhibited as he set out on a bombing spree that killed three and injured 23 others.

CLICK HERE TO WATCH A NIGHTLINE SEGMENT ON LONE WOLF KILLERS

"It brings back horrible memories and some sense of recognition," said David Kaczynski, who eventually recognized the writings of the Unabomber as those of his brother and alerted authorities. "I think when we talk about a lone wolf we have to make distinctions -- people like my brother, my brother was not just a lone wolf, he was diagnosed with very serious mental illness, schizophrenia. And this case, from what little I know, from what I can tell, has schizophrenia written all over it."

Kaczynski stressed that most people with mental illnesses are not violent. But there are cases, he said, "where the psychotic delusions precipitate psychotic behavior and it's very, very difficult to predict."

CLICK HERE TO WATCH AN EXTENDED INTERVIEW WITH DAVID KACZYNSKI

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