After Dr. Gilberto Nunez was charged with murder, patients began deserting him. Illustration by Adrian Tomine

“My dentist was recently indicted for murder.” It sounds like a droll line that you’d use at a dinner party, but in my case it’s true. On October 15, 2015, Dr. Gilberto Nunez, whose patient I had been for many years, was indicted for killing his friend Thomas Kolman, of Saugerties, New York, by getting him “to ingest a substance that caused his death.” There were also two forgery counts: allegedly, Nunez had been posing as a C.I.A. agent. He’d apparently told people that he was authorized to implant tracking devices in patients’ teeth. It wasn’t the kind of news you wanted to hear about your family dentist.

Kolman’s death occurred before dawn on November 29, 2011, in the parking lot of a Planet Fitness gym in Ulster, fifteen minutes south of Saugerties. Kolman, who was forty-four, often stopped at the gym on his way to work. Later that morning, after he failed to show up at the office, his wife, Linda, found his body in the driver’s seat of his car. Four years afterward, Nunez was charged with murder.

According to the prosecutors, Nunez, who is fifty, was having an affair with Linda Kolman. He impersonated a C.I.A. officer as part of a scheme to prod her to abandon her husband. When she ended the affair, Nunez threatened suicide. Eventually, the suicidal impulse turned homicidal. On the morning of Thomas’s death, Nunez met him at the gym. Security-camera footage apparently showed their cars sitting next to each other for twenty-eight minutes, then Nunez’s car pulling away. Midazolam, a sedative used only by doctors and dentists, was found in Thomas’s body, and vials of the drug were discovered in Nunez’s office. A Wikipedia search for midazolam was logged on his computer.

I’d resigned myself to looking for a new dentist, but in April, 2016, I broke a tooth and needed urgent attention. By then, Nunez, having spent forty-one days in the county jail, was out on bail, and I called for an appointment. It wasn’t hard to get one. His office, in Kingston, which neighbors Ulster, was subdued. His son, who worked at the reception desk, looked depressed. So did his office manager, who had assured me with touching (but surely misplaced) loyalty that Dr. Nunez was innocent.

I hadn’t given much thought to the social protocols of the situation, but when Nunez beckoned me into the examining room I mumbled, “I’m sorry for your troubles.” He nodded gravely and said, “Thank you for your support.” That’s not quite what I meant, I thought, but before I could say anything more the hygienist was tilting me back in the chair.

After the procedure, I asked Nunez if we could discuss the case, and to my surprise he enthusiastically agreed. Speaking in accented English—Nunez was born in the Dominican Republic—he told me his version of the story. When he went on trial, a few weeks later, almost every detail of his account was corroborated.

He had become friendly with the Kolmans in 2010. Thomas was a physical therapist, Linda a hospital administrator. Money troubles and stress had taken a toll on the couple: an earlier marriage had left Thomas with hefty divorce payments, and Linda’s daughter (also from an earlier marriage) had health problems. Linda and Thomas had a son, and he was having difficulties at school. Nunez, who was then separating from his wife, became Linda’s confidant as they waited for their boys to finish lessons at a local karate school. He also became friendly with Thomas, but in December, 2010, he and Linda began an affair. Soon Nunez was in love, and wanted Linda to tell Thomas what was going on. Linda wasn’t ready to end her marriage.

Nunez told me that he became so frustrated by the secrecy that he dreamed up “a horrible idea.” In July, 2011, he bought a disposable phone and, posing as a woman named Samantha, sent Thomas a series of texts designed to “steer him toward the knowledge that his wife was having an affair with the dentist.” Thomas confronted Linda, who confessed. She then confronted Nunez. He denied sending the texts and, doubling down on the lie, accused Thomas of sending them to himself. Shortly afterward, he left a message on Thomas’s phone, full of tearful protestations of love for both of them, along with histrionic farewells to the world. Thomas called emergency services, which sent someone to check on Nunez, who told the officer that he’d had “a moment of weakness” but was now O.K.

However, he still hadn’t admitted sending the Samantha texts, and, when he heard that Thomas might hire a detective to investigate, he committed a final act of lunacy. Telling the Kolmans that he knew a C.I.A. computer expert who could determine the origin of the texts, he offered his office I.T. guy five hundred dollars to pose as the expert and meet with the Kolmans. The plan called for the I.T. guy to flash a phony C.I.A. badge. Nunez showed me on his computer where he had bought the badge: a Web site selling novelty I.D.s. (Several of the I.D.s featured photographs of Rowan Atkinson, making his Mr. Bean face.)

The details are disputed after this point, but all sides acknowledge that the I.T. guy never met with the Kolmans. Instead, Nunez went to Thomas’s office himself, dropped to his knees, admitted that he’d sent the texts, and begged for forgiveness.

One would think that all this drama would have cooled relations between the Kolmans and Nunez. But Thomas, though still hoping to save his marriage, accepted the affair. Stranger still, he and Nunez became closer, texting each other dozens of times a day. Sometimes the three went out together. Other times, Thomas babysat while Nunez and Linda went out. On Thanksgiving, Nunez attended the Kolman family’s gathering, where the two men talked about opening a business together. Two days later, the three took their children to an Olive Garden. On Monday, November 28th, Nunez and Linda had an early dinner together before returning to their respective homes. Later, Thomas and Nunez texted each other—bro this, bro that—as they watched the Giants game on TV. A few hours later, Thomas was dead.

Nunez’s account diverges radically from the prosecution’s here. Nunez told me that he went to bed halfway through the game and didn’t learn of Thomas’s death until late the next morning. The prosecution’s suggestion was that he was waiting for Thomas outside the gym with a cup of poisoned coffee. Linda, the prosecutors claimed, had definitively broken off the affair during the dinner before the Giants game, devastating Nunez. This wasn’t true, Nunez assured me, adding that evidence at the trial would confirm that Linda had retained her ardor for him. Though two midazolam vials were found in his office—part of an emergency kit to calm someone having a seizure—they were unopened. As for the alleged footage of his car outside the gym, the camera was too distant for a viewer to make out anything but the glare of headlights. Someone had met Thomas outside Planet Fitness, Nunez agreed, but it wasn’t him.

“These people have ruined my life,” he said. He anticipated more than a million dollars in legal fees. Patients were deserting him. His good name had been tarnished. Nevertheless, he was confident of being acquitted, and he had the full support of his new wife, a singer named Yameil, whom he had married in 2014.