Arthur Gary Bishop, in clinical terms, is a homosexual pedophile, consumed by an attraction to young boys.

No one knows how many pedophiles there really are in society, but even among this class of deviates, Bishop was clearly in his own ultraperverted category.Even after a lethal injection ends the life of the 35-year-old murderer Friday morning at the Utah State Prison, questions will remain about this man who defied psychological reason and left mental health professionals wondering what really made him tick.

"If there is a typical picture of a pedophile or sadistic child molester, he didn't fit either," said Dr. Louis Moench, one of three local psychiatrists appointed by the court to determine if the child-killer was competent to fire his attorneys and seek his own execution.

But Moench admits that until the past decade, scientific textbooks have been sparse in information about pedophiles, whose sexual interests are focused exclusively around children.

Dr. Paul L. Whitehead said pedophilia is the most common of all sexual perversions as far as the criminal justice system is concerned.

"That's probably because when you have children as victims, the legal system takes notice," the child psychiatrist said. "But overall as a phenomenon, it seems to be uncommon. And pedophilic encounters resulting in physical injury or death are rare."

Bishop proved to be the exception time and time again.

Whitehead, public affairs representative for the Utah Psychiatric Association, said studies show that over 80 percent of pedophiles were sexually molested as children. Many think that this molestation fixates them, stopping their sexual development at the age they were abused.

But Bishop apparently didn't have that kind of childhood.

"I didn't detect anything about his home life or upbringing that would suggest any previous childhood experience with homosexuality or pedophilia," Moench said. Bishop's father was away from the family working two jobs much of the time and didn't demonstrate a great deal of warmth and affection. But such is the case with many fathers. "This doesn't explain either pedophilia or violence."

Moench said Bishop spent a good deal of his time doing things to please his mother. "He did a lot of things that he didn't feel emotionally committed to - like church assignments." Although Bishop told Moench that he was aware at about age 14 that he definitely had a sexual attraction to younger boys, he was embarrassed by his feelings and didn't discuss them with anyone.

Bishop served a mission for his church but was depressed and demoralized and felt he was an ineffective missionary, the psychiatrist said.

"He didn't feel that he belonged in the church anyway because he was too different," Moench said. "He felt the church was for well-behaved people, and he was eventually excommunicated."

Bishop lived a private life condemned by society.

Whitehead and Moench said true pedophiles usually are timid, rather inadequate individuals, who are uncomfortable with and even fear adult female relationships. They infrequently marry, and then usually only as a way of having children around. Friendships with adult females are also often for that purpose.

Most pedophiles aren't aggressive people. In fact, they have a sense of failure in life, a low self-esteem and an inability to relate very well in an adult world. Yet Moench said he found Bishop to be polite, congenial and eager to please. "He's a person who wouldn't be hard for the average adult to like."

Pedophiles, the psychiatrists said, seem to have an attraction to children because they feel on a more emotional level with kids.

Their victims are usually immature children and can be members of their family, acquaintances or total strangers.

Three of Bishop's victims - Alonzo Daniels, Danny Davis and Troy Ward - were strangers, wandering alone when Bishop attracted them with promises of candy, toys or food.

Whitehead said the driving force behind pedophiles' actions is their pervasive sense of powerlessness. They compensate by arranging situations that enable them to feel powerful, controlling and dominating. That's why their encounters are with children.

"Some studies suggest there can be a type of attention nurturance to a child in a pedophilic relationship, but there is almost always psychological damage," Whitehead said. "Most pedophiles maintain they are not exploiting children; they are merely offering love. And sometimes the children wouldn't identify it as being exploited. Usually these victims can't separate affection from exploitation, which affects relationships for the rest of their lives."

But Whitehead said pedophiles' involvement always has a degree of sadism, aggression and coercion - which can range from subtle and affectionate to violent and forceful. Pedophiles who use violence fall into a unique category - in between a child rapist and the "affectionate" pedophile.

Bishop had components of both.

His first two killings, Moench said, were impulsive. He did not plan to kill Daniels, 4, or Kim Petersen, 11.

Bishop confessed to Moench that after the first killing, he felt "goodness leave him." From then on it was not hard to do it again - and again. Moench believes Bishop would have continued to kill had he not been caught.

"Bishop remembers knowing in advance as soon as he saw these little boys on at least two instances that his involvement with them would not only end in an erotic experience, but he would kill them," the psychiatrist said. "Unlike true sadists, it was not pleasure in the violence or murder that motivated these killings. The murders were carried out over shame of being found out."

When he got disgusted with the children and himself and feared they would tell, he hit a fatal blow with hammer or drowned them. One he shot in the back of the head, and one he strangled.

Unlike some sadistic murderers, Moench said Bishop had fleeting remorse after killing his first victim. While carrying one child's hidden body to the trunk of his car, he passed a distraught woman saying the name of that child.

"He surmised it was the kid's mother, which in fact it was," Moench said. "She couldn't find her youngster. . . ."

Bishop said he felt remorse at that time - but he soon got over it and subsequently was able to deny or overcome any sense of remorse from killing other children.

Until now.

In a motion filed by Bishop on Feb. 16, the killer wrote, "True justice rightfully demands my life for the horrible crimes I committed."

But Whitehead doesn't believe Bishop wants to die only to seek atonement.

It could, he said, be another attempt by Bishop to be in control. He killed five people and, ironically, the state has given him the opportunity for a final time to exercise this option of determining somebody's death.

That, Whitehead said, may give him a final sense of power.