If there was one constant in Patrick Edward Purdy's short and troubled life, it was his itch to be somewhere else.

He started roaming early, at age 14 running from an unhappy home, and he seldom stopped over the past 10 years. But the demons chasing Purdy finally caught up with him last Tuesday as he ended his transient life in a violent homecoming at his old elementary school here.Purdy, 24, opened fire with a semi-automatic rifle on a crowded playground. He killed five children and wounded 29 other youngsters and a teacher. Then he turned a pistol on himself and delivered a final, fatal shot.

As residents of this central California town reeled in horror, people who knew Patrick Purdy struggled to understand how the troubled young drifter could have turned into a murderous commando.

Despite the public nature of his schoolyard slaughter, Purdy held a rage as private as it was explosive. He knew how to build walls around his emotions, sometimes shielding a darker nature from those who thought they knew him well.

Where his aunt and uncle saw a polite young man working hard to overcome some bad breaks, others saw a surly loner who plunged into suicidal moods, tormented by alcohol, drugs and a world he believed had done him wrong.

Some former co-workers remember a hard worker who kept to himself and harmed nobody, and relatives say Purdy was well-read and articulate. But others knew Purdy as the high school dropout described in one police report as dangerous and suffering from "mild mental retardation."

Some saw him when he was down and out, with a scraggly beard and ragged clothes. Others saw a clean-shaven, handsome man with short blond hair, tanned face and piercing blue eyes.

Nobody saw him for long.

Purdy crisscrossed the country, living and working in Stockton, Los Angeles, Florida, Tennessee, Connecticut and Texas, among other places. He hitchhiked, or drove beat-up old cars, sometimes abandoning them when they broke down.

"He was always on the go. He couldn't keep still," said his aunt, Julie Michael.

His transient ways began long before he had a choice in the matter.

Patrick Edward Purdy was the son of an Army man, Patrick Benjamin Purdy, born while the elder Purdy was stationed at Fort Lewis near Seattle. The parents split within a few years, and Purdy stayed with his mother, Kathy, who took him to South Lake Tahoe, Calif.

They also apparently lived for a while in Stockton. School records show that Purdy attended kindergarten through third grade at Cleveland Elementary School, scene of last week's slaughter.