Descent Into Evil: He was a soldier, a Muslim convert, and a man who had failed in love and business, who clung tightly to a teenager not his son. The story of a journey into darkness and murder--and the investigation that brought a killing spree to an end.(John Allen Muhammad)

Byline: This story was reported by Pat Wingert, Suzanne Smalley, T. Trent Gegax, Daniel Klaidman, Mark Hosenball, John Barry and Mark Miller in Washington; Anne Belli Gesalman in Baton Rouge; Julie Scelfo in Richmond; Andrew Murr in Tacoma; Ana Figueroa in Bellingham; Kevin Peraino and Catharine Skipp in Antigua; Arian Campo-Flores in Montgomery, Ala.; Sarah Downey in Chicago; Michael Isikoff in San Francisco, and Seth Mnookin in New York. The story was written by Evan Thomas.

John Williams had been a talkative little showoff when he was growing up. His grandfather, who raised him after his mother died and his father disappeared, nicknamed him "Governor." He was still strutting when he went to visit his family in Baton Rouge, La., about nine months ago, with a man he said he was helping travel back to Jamaica in tow. He claimed that he was in the immigrant "import-export business," according to his cousin Charlene Anderson. "He said he helped people who were in trouble get in and out of the country. He was so well dressed, kind of like he had been put up on a shelf," she told NEWSWEEK. But when John, who had changed his last name to Muhammad, showed up a few months later, late last summer, he was dirty and hungry, and his posturing had veered into dangerous delusion. Summoning Anderson into the kitchen, he closed the door and unzipped a long green duffel bag. Inside the bag was a case, and inside the case was a rifle. Muhammad explained that he was working for a secret Special Forces group to recover missing C-4 explosives stolen from a military base by drug smugglers. Muhammad was accompanied by a teenage boy named Lee. "Lee's not my son," Muhammad explained. "He's on the special team with me. He was hired to blend in with the juveniles on the street. See that boy? He's highly trained." She asked why he didn't work through local law enforcement. "He told me he couldn't do that because nobody knew they existed," she says. Cousin Charlene wasn't sure what to believe. "I thought it was very strange. It really spooked me."

If authorities are right, by the time Muhammad and his young sidekick were done last week, many millions of people had been traumatized by their grotesque playacting. The two pretenders left a blood-soaked trail as they wandered from Washington state to Alabama to metropolitan Washington, D.C. They left little catch-me-if-you-can clues and odd allusions to Jamaican music and folklore. They methodically shot people of all ages, genders and races, and they made outrageous demands for money. But it was never very clear what they were really up to, aside from trying to get attention.

That they got. Before moving in for the arrest last week, the Feds and the police prepared for pitched battle. Local police SWAT teams, the FBI's elite Hostage Rescue Team and other state and federal paramilitary units strapped on their body armor and shouldered their automatic weapons. For more than two hours, at a McDonald's parking lot near the highway rest stop where the snipers' car had been spotted, the assault was elaborately staged and mounted. Finally, at about 3 a.m., as choppers roared overhead and searchlights glared, the black ninjas leapt into action and encountered the enemy... peacefully dozing. One official said the sniper suspects barely stirred as police smashed through the windows of the car and screamed at the men to surrender. "They practically slept through the takedown," the official said.

Maybe they were just worn out by shooting people (13 over 21 days, plus two more in Alabama in late September; 11 died). Maybe they hadn't heard the news reports that the Feds were closing in. Whatever the case, few law-enforcement officials expected such a docile ending to a ghastly siege that had terrorized metropolitan Washington and transfixed the media. The suspects, John Allen Muhammad, 41, and John Lee Malvo, 17, were penniless drifters. They were not stumblebums. Muhammad, though an insubordinate soldier, had been a skilled marksman in the Army. He had transformed his aged Chevy Caprice into a kind of Rube Goldberg killing machine by cutting a hole in the trunk to help create a hidden sniper's perch. He had trained his young friend Malvo, whom he reportedly called "Sniper," to shoot a human being from a hundred yards or so. Police believe that the two men took turns and theorized that Muhammad took the more difficult head shots, while Malvo aimed for the victim's torso.

But demonic geniuses they were not. As the death toll mounted and the talking heads blathered, an ever more menacing picture of the sniper had seized the public imagination. He was the Scarlet Pimpernel with an assault weapon, clever, taunting, elusive, ghosting about in a white van that seemed to magically melt through massive dragnets. Not just the cable-TV criminologists but also the government's own experts were fooled. Until the last couple of days, most top officials at the state-local-federal joint command center in Rockville, Md., thought they were looking for an "intelligent, well-organized white male," one veteran federal investigator told NEWSWEEK.

Someone capable of randomly picking off pretty much anyone who walked into his gun sights, day after day, must be in the thrall of some frothing-at-the-mouth psychosis--if not the Devil, certainly his disciples. Right? Some top federal officials had suspected that the snipers were Qaeda assassins. Muhammad may have conceivably been a sympathizer or a self-recruited terrorist. A convert to Islam who claimed to have provided security for Louis Farrakhan during the 1995 Million Man March on Washington, Muhammad had been heard by neighbors praising the 9-11 hijackers for their efficiency. But his motives, as well as the nature of his relationship with the teenage Malvo, remain murky. His anger at his ex-wife over a particularly ugly child-custody battle appears to have enraged him more than any political or religious obsession. He is a chilling figure, but mostly because he seems to have shown that almost any sore loser with a store-bought gun and a sniper scope can paralyze the nation's capital. Imagine what a few well-trained teams could…