The Redneck Riviera beckoned. It was a Friday afternoon in early 2014 and Robert Bentley was ready for the weekend. Not that his workweeks were so bad. Bentley, the governor of Alabama, was in the homestretch of his first term and on a glide path to his second. Polls put his approval rating as high as 80 percent. The state's unemployment rate had dropped to a five-year low on his watch, and there was incipient chatter about how, after his all-but-certain landslide re-election in November, he might make a run for the White House.

By all appearances, Bentley, then 71 years old, had taken perfectly to his late-in-life foray into politics. The perks of the job were nothing to sniff at, either. In addition to the state troopers at his beck and call, the governor adored the white-columned mansion with the personal chef and the private garden that boasted two types of okra. And then there was the helicopter. Thanks to the miracle of state-operated rotor-borne flight, he could be at his family's vacation home on Alabama's Gulf Coast in under an hour. As he lifted off from Montgomery and flew south, Bentley sat contentedly, stealing occasional glances out the window at the chinaberry trees and wire grass below. He was a man in full—and completely unaware that he was choppering straight into a trap.

Accompanying him on the flight was his wife, Dianne. The couple had been married for almost 49 years, raised four sons, and been bestowed with seven lovely granddaughters. For many happy decades, Robert, a doctor with a thriving dermatology practice in Tuscaloosa, would hustle home every day for lunch with Dianne. More recently, as governor, he'd return to the mansion from the state capitol in the early evening and sweet-talk her in the kitchen. Come Sundays, they were mainstays at First Baptist of Tuscaloosa, where Robert was a deacon and Dianne worked in the nursery. They seemed every bit the state's benevolent grandparents—a model Christian couple for Alabamians of all political stripes.

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But a few months earlier, Dianne started to notice something changing in the governor. As she later told a confidante, Robert was more taciturn when he came home from work and was more sparing with his kisses. She was puzzled that her husband—a man so unconcerned with how he looked that his advisers would remind him not to wear his tattered gardening pants out in public—had started sporting bright orange socks and snazzy ties. Dianne, a woman whose personality is as demure as her bobbed silver hair, tried to put these things out of her mind. But the oddities were stacking up.

The governor's daily schedule, which once meticulously accounted for where he went—and with whom—now contained blocks that were vaguely labeled “Hold.” According to people close to Dianne, when she asked him what he was doing during these periods, he became defensive and wouldn't say. Occasionally, Dianne's phone would buzz with text messages from her husband containing a red-rose emoji—messages so unexpected and out of character for the governor that she wondered if they were intended for someone else. On one occasion, as they exited church after a prayer service, Dianne reached for Robert's hand, as she always did, only this time he brushed it away.

Dianne tallied the worrisome signs in a notebook until, these sources told me, the list grew so long that she felt compelled to share it with one of the young women who worked for her in the First Lady's office. The aide confessed that she'd noticed some changes in the governor, too—especially in how he was acting toward one of his staffers, a woman nearly 30 years his junior named Rebekah Mason.

If something was going on, Dianne needed some evidence. That's when, according to people close to Dianne, her aide told her that the same iPhone on which she was receiving the incongruous red-rose emojis was also equipped with a voice recorder. A plan was hatched.

Photo by Phillip Toledano

When the helicopter touched down on the Gulf Coast near the Bentley family beach house, Dianne had everything she needed. Here, she knew she and her husband would be alone—unattended by the retinue of aides and state troopers that hovered in their wake in Montgomery. Here, she knew she could slip away for a walk on the beach, trusting that her husband, who didn't much care for the cool weather, would stay behind. Here, she knew she could also leave behind her purse with that iPhone surreptitiously recording inside. What she couldn't know for sure, of course, was what her husband might say or do while she was gone. “Dianne, you gonna freeze,” Robert shouted to his wife as she headed outside. “Don't you need a coat?”