There are many expensive houses here in Brecken Hill, an enclave on the edge of Aylesford, in the Hudson Valley. Situated on the east side of the Hudson River, about a hundred miles north of New York City, it’s like the Hamptons, but slightly less pretentious. There’s old money here, and new. Down the long private drive, past a clump of birches, there it sits: the Merton home, on its vast expanse of lawn, presented like a cake on a platter. A glimpse of a swimming pool to the left. Behind is a ravine, and thick trees on either side of the property guarantee privacy. This is prime real estate.

It’s so still and undisturbed. A weak sun is out, and some scudding clouds. It’s four o’clock in the afternoon on Easter Monday; elsewhere, children are greedily finishing off their chocolate bunnies and foil-wrapped eggs, gauging what’s left and eyeing how much remains in the baskets of their siblings. But there are no children here. The children have grown up and moved away. Not far, mind you. They were all over just yesterday, for Easter Sunday dinner.

The place looks deserted. There are no cars in the driveway—they are shut away behind the doors of the four-car garage. There’s a Porsche 911 convertible; Fred Merton likes to drive that one, but only in the summer, when he throws his golf clubs in the trunk. For winter, he prefers the Lexus. His wife, Sheila, has her white Mercedes with the white leather interior. She likes to put on one of her many colorful Hermès scarves, check her lipstick in the rearview mirror, and go out to meet friends. She won’t be doing that anymore.

A house this grand, this polished—glossy white marble floor beneath an elaborate, tiered chandelier in the entryway, fresh flowers on a side table—you’d think there must be staff for upkeep. But there’s only one cleaning lady, Irena, who comes in twice a week. She works hard for the money. But she’s been with them so long—more than thirty years—that she’s almost like family.

It must have looked perfect, before all this. A trail of blood leads up the pale, carpeted stairs. To the left, in the lovely living room, a large china lamp is lying broken on the Persian rug, its shade askew. A little farther along, beyond the low, glass coffee table, is Sheila Merton in her nightclothes, utterly still. She’s dead, her eyes open, and there are marks on her neck. There’s no blood on her, but the sickening smell of it is everywhere. Something awful has happened here.

In the large, bright kitchen at the back of the house, Fred Merton’s body lies sprawled on the floor in a dark and viscous pool of blood. Flies buzz quietly around his nose and mouth. He’s been viciously stabbed many, many times, his fleshy throat slit.

Who would do such a thing?