THERE ARE KILLERS AND THERE are killers. Killers get drunk and blow away their cheating husbands with a shotgun or hire someone to do it. Killers plot, plan, and most of all, enjoy their work. When you read about one, you think, “There but for the grace of God . . .” When you read about the other, you wonder just how twisted and depraved God permits humans to get.

It’s the second group I’m interested in. I’ve been around these scumbags all my professional life, and I’m always struck by their ordinariness. Whether the subject is a snarling beast like Kenneth McDuff or a smiling shark like Charles Harrelson, interviewing a killer is tricky business. What do you ask a killer? So, how’s your day? Yes, I see what you mean. What’s your favorite color? I should have guessed. Concerning the accusation that you bludgeoned that nun with a crowbar . . . I take your point.

Beyond the awkwardness, you can’t trust what they tell you. Their motive can be malice, money, or revenge. Regardless, every killer is a psychopath to some degree. Most can fool a polygraph as easily as they can fool an interviewer—or, for that matter, themselves.

The first killer I ever interviewed was Gene Paul Norris, a notorious badass in Fort Worth in the mid-fifties. He had been hauled in on some vague charge and had requested to talk to a reporter, any reporter. I was a cub on the police beat for the Star-Telegram, raw as a lamb chop, but I was the only guy available in the pressroom. Norris was a high-profile player in what was known as the Dixie Mafia, and every newshound in town would have given his trench coat for an interview. Envisioning a page-one byline, I grabbed a fistful of notepaper and rushed to the holding cell. Norris was seated in a chair, the only piece of furniture in the room, and he smiled and offered me his seat.

In his mid-thirties, Norris was an angular, rawboned man, taller than his mug shots suggested, more cordial than I had expected, and far less menacing. His cat-gray eyes had a soothing effect, and he talked with such apparent sincerity that I ran out of paper before I could ask a question. Later, when I reviewed my notes, I realized that the only straight thing he’d told me was a telephone number to call, with the message that he was back in jail. An older and more experienced newsman eventually informed me that I had fallen for a scam Norris regularly pulled on young reporters. It was his way to get word to his lawyer. (In those days, the Fort Worth police weren’t big on civil rights.) A few months after our chat, Norris was ambushed and shot to pieces by a posse of several dozen lawmen, at which time the police wrote off forty-something unsolved murders, most of them gang related. Gee, and he had seemed like such a nice guy.

The strangest killer I ever encountered was a smarmy nerd named Tim Scoggin. He had been an apprentice mortician in Llano before moving to San Angelo, where he branched out into real estate and other business ventures. Scoggin’s ambition was to get rich, and his hobby was painting flowers and lacy designs on porcelain urns. Though he was in his early thirties, most of his friends were old women and, occasionally, old men. They found him a pillar of strength, always there to cook their meals, deliver messages, run to the pharmacy, drive them to doctor’s appointments.

He became the adviser and sole companion of two elderly sisters in Llano, Cordelia and Catherine Norton. The sisters lived alone in the old family mansion, high on a bluff overlooking town; their only visitor was Scoggin, who made trips from San Angelo almost daily to check on their well-being. When they died, in February 1988, one day apart, Scoggin took charge of their affairs and had them cremated. Five weeks later another of Scoggin’s elderly friends, Olgie Nobles, of San Angelo, died after experiencing uncontrollable vomiting, diarrhea, and stomach pains—the same symptoms the Norton sisters had suffered. Who could have guessed Scoggin had been diluting their Maalox with rat poison?

Scoggin had been in jail for four months when I interviewed him, and he wasted no time in delivering a most unflattering critique of the criminal justice system. A diminutive fellow with jug ears and rust-colored hair, he reminded me of Howdy Doody. His voice was a squeaky soprano; on the phone he sounded like a woman. But he was very correct and businesslike too—a Mr. Belvedere in jailhouse issue—and he continued conducting his affairs from his cell. He told me he’d never been around the lower class and saw himself as a breed apart from the other inmates. “I have always been a conservative Republican,” he explained. “My expectation of jail was luxury living, color TVs, suites like the Ritz. I’ve changed my point of view.” Scoggin is still in prison, serving a life sentence.

Convicted of killing a Dallas police officer, Randall Dale Adams had been in prison for ten years, three of them on death row, when I interviewed David Ray Harris in 1987. It had been almost eleven years since the murder of officer Robert Wood, who was shot five times at point-blank range after he pulled over a motorist for a minor traffic violation. By then I was convinced, as were others who had reexamined the evidence, that the police and the prosecutors had nailed the wrong man—and had done so deliberately to expedite a successful conclusion to a highly publicized cop killing. Adams had no criminal record and no motive, but he failed a polygraph. His only alibi was Harris, whom he’d met the morning of the murder when Harris stopped to offer him a ride. Adams didn’t know that the car was stolen or that Harris was a fugitive. Already on probation for juvenile offenses, Harris had an obvious motive for killing the officer: An arrest would have meant jail time. Moreover, in the days just after Wood’s murder, Harris had bragged to friends in Vidor that he had blown away “a pig in Dallas.” But Harris passed his polygraph. Dallas police officers were also influenced by the fact that he was sixteen and therefore not eligible for the death penalty. When Harris agreed to testify against Adams, the case was essentially closed.

Harris was himself on death row when I interviewed him. Though he was then 26, the boyish charm that had made him so engaging at the time of the trial was still evident. He had done two previous terms in prison and was awaiting execution for a crime that was straight out of the psychopath’s handbook. He had broken into an apartment in Beaumont, dragged a young woman kicking and screaming to his car, and pumped five slugs into her boyfriend when he attempted a rescue.

Of course, Harris understood that I was there to talk about what had happened in Dallas, not Beaumont, and he was surprisingly at ease. When I said, “Adams didn’t kill that cop, did he?” a thin smile played across his lips and he began to shake his head no. “Did you kill him?” I asked. Harris’ smile wavered, then he said he couldn’t answer that, at least for the moment. “It can’t hurt you now,” I told him. “It can’t help me either,” he replied. After a moment he added, “But if it ever gets to the point where they’re strapping me on that gurney to die, stand by for a statement.” The case against Adams was dismissed in 1989—largely because of evidence assembled by filmmaker Errol Morris for his award-winning documentary, The Thin Blue Line—but a quarter of a century after the murder, Harris remains on death row.

Charles Harrelson, who is doing two life sentences for assassinating federal judge John Wood in 1979, was a professional hit man and damn proud of it. He bragged that he’d never held an honest job, and he loved his image as a killer so dearly that he boasted of hits he’d never made. In the seventies, when he was serving time on a gun possession charge at Leavenworth, one of the toughest prisons in the country, Harrelson convinced other inmates that he was in for murder. The late Houston defense attorney Percy Foreman said he’d never seen Harrelson more content than during those years at Leavenworth. “He probably had more respect there than anywhere he’s ever been,” Foreman told me. “The hired killer has a certain aura.”

In 1980, before he was indicted for Wood’s murder, Harrelson wrote in his diary, “I never killed a person who was undeserving of it.” The next day, he was arrested after a six-hour standoff with police officers in the desert near Van Horn. He had been shooting cocaine all afternoon, and when he finally agreed to surrender, he also confessed that he had assassinated President Kennedy. A short time after that, I interviewed Harrelson in the Bexar County jail in San Antonio and asked him if that astonishing confession was true. He smirked and said, “Yeah, I did the man.” He knew I didn’t believe him, but that was part of his game. Harrelson was a con, a manipulator, a cardsharp who won by cheating. He was so adept at cards, or so he claimed, that Las Vegas had banned him. Yet this master of the con killed his first two victims for a couple thousand dollars and did a federal judge for a sum—$250,000—that any high roller would have viewed as pocket change. For all that, Harrelson had a certain roguish charm. Under other circumstances, I thought at the time, I might have enjoyed knowing him.

There was nothing remotely charming or likable about Kenneth McDuff, who was executed in 1998 for murdering a series of young women in Central Texas in the early nineties. McDuff picked his victims at random and took enormous pleasure in his particular style of foreplay, which included torture and rape. He ditched the bodies in graves he had dug beforehand, and sometimes relived great moments by visiting the graves of past victims. When he learned that a woman he had raped and left for dead some twenty years earlier had given birth to his daughter, he looked up the young woman and offered to be her pimp.

Shortly after McDuff was arrested and returned to Waco to be tried for capital murder, I had an opportunity to interview him. But I couldn’t bring myself to do it. The thought of sharing a room with that monster gave me chills. I’d seen too much already.