Monday evening, 500 or so residents of Covina, California gathered at the Royal Oak Intermediate School to discuss the horrific Christmas Eve slayings committed by Bruce Pardo. Pardo, dressed as Santa Claus, walked into a family gathering at his ex-in-laws' home, shooting a 9-year-old girl in the face and then killing nine other people. Before escaping and committing suicide himself, he burned the house to the ground.

According to police, Pardo had hoped to kill other people, too, including his mother, his wife's divorce attorney and the attorney's family. They believe he had been planning the carnage since June - perhaps even earlier.

Because of Pardo, 13 young people are orphans. Still others are without one of their parents.

What makes a man, who appeared to others to be quirky, but friendly, commit such an atrocity? How is it possible that the same person who had participated in a seemingly rational way in divorce proceedings could have done so with mayhem on his mind? How could he have wished the owner of his favorite coffee shop-the Montrose Bakery and Cafe-a merry Christmas just several hours before the slayings?

We know some of the stresses Pardo was facing. He had lost his job. His marriage had dissolved in the wake of his wife having learned he had abandoned a son she knew nothing about, a son left brain-damaged by nearly drowning while Pardo was to be watching him. Perhaps Pardo felt lingering guilt and grief over that tragedy.

Yet, in my 16 years as a psychiatrist, I have met hundreds of men and women who have shouldered equal or greater psychological burdens without their circumstances triggering violence of any kind. I have been privileged to see many of them face the loss of children, homes, marriages or their own health by looking inside themselves for strength - and finding it.

Pardo apparently had no such reserves of character upon which to draw, no hope for the future, no empathy left for others. He seems to fit into that category of men I have met in my work as a forensic psychiatrist who, faced with painful changes over which they lacked control, came to see their life stories - including the people in them - as ending, done with ... over. It is as if they were collecting scripts from actors in a play that was going badly and being shut down. Then the curtain fell.

For Bruce Pardo, I can theorize (even without interviewing him), there had to be a deep-seeded belief - perhaps an unconscious one - that loss of control or perceived abandonment had always meant chaos and terror. There may have been unavoidable suffering in his own life as a child, suffering he could do nothing to prevent, suffering that left him, long into his adult life, with a child's intense brand of terror at being powerless. There can be no consoling such a "man" when events - even those of his own making - seem to be rendering him isolated, subject to forces (like job loss and divorce decrees) he cannot bend to his infantile will, impotent.

Those feelings of impotence, I believe, may have been the ones turned upside-down and inside-out in the months leading to the Christmas Eve carnage in Covina. They may have been the ones that became fuel for a pathological and sinister plot that, in his own twisted mind, turned Bruce Pardo, for one terrible night, into the strongest man on earth, wielding the power of life and death over others, as though the frailties in his own psyche could somehow be camouflaged, even beyond his own recognition, by a storm of bullets and shield of flame.

Dr. Keith Ablow is a psychiatrist and member of the Fox News Medical A-Team.