Unfortunately, Cook's appointed foster mother was more interested in earning money from the boy than raising him correctly. Two years running, Cook was given bicycles for Christmas, and they were immediately repossessed for lack of payment. As he entered adolescence , Cook began to run the streets at night and practice petty theft; upon his first arrest, he told the court he would prefer reform school to his foster home. Released a few months later, Cook immediately robbed a cab driver of eleven dollars, earning a five-year stretch in the reformatory. Violent outbursts there resulted in a transfer to state prison, where he earned a reputation as a brawler. Once, Cook nearly killed a fellow inmate with a baseball bat, the incident resulting from a joke about his droopy eyelid.

Finally released in 1950, at the age of 22, Cook stopped in Joplin long enough for a reunion with his drunken father, moving west from there with the expressed intent to "live by the gun and roam." He picked up the gun -- a .32 pistol -- in El Paso, Texas, traveling as far as California before he doubled back, wandering aimlessly across country. The words "Hard Luck," tattooed across the fingers of his left hand, foretold the fate of hapless strangers who would cross his path.

In Lubbock, Texas, on December 30, 1950, Cook abducted a motorist at gunpoint, pushing north toward Joplin. His hostage escaped in Oklahoma, and Cook ran out of gas on Highway 66, between Tulsa and Claremore, on New Year's Eve. Carl Mosser, his wife and three children were bound for New Mexico when they stopped to help another motorist in trouble, and their trip became a nightmare from the moment they laid eyes on William Cook.

Flashing his pistol, Cook ordered Mosser to "drive him around." Stopping for gas and food in Wichita Falls, Texas, Mosser tried to disarm his captor, but Cook was quicker and stronger, firing several shots at a grocery clerk who tried to intervene. Over the next two days, Mosser drove Cook through New Mexico, Texas, and Arkansas, winding up in the gunman's old stamping grounds, around Joplin. There, Cook massacred the family (and their dog), dumping the bodies down an abandoned mine shaft before continuing his odyssey.

His bloodstained car broke down in Osage County, Oklahoma, and Cook flagged down a deputy sheriff, disarming the officer, whom he left in a roadside ditch, his hands bound. Driving the stolen patrol car, Cook stopped a traveling salesman, Robert Dewey, and changed vehicles again, forcing Dewey to head for California. On arrival, Cook dispatched his hostage execution-style, the corpse and car alerting lawmen to his presence on the coast.

Pushing south, Cook crossed the border at Tijuana, picking up two more male hostages en route. On January 15, 1951, he was recognized by the police chief in Santa Rosaria and disarmed without a struggle. Returned to California for trial, on murder charges, Cook was convicted and sentenced to die. He was executed in San Quentin's gas chamber on December 12, 1952.