The Gold Coast by Nelson DeMille

John Sutter, a Wall Street lawyer living in the wealthy enclave of Long Island’s North Shore, has built his life on privilege, order, and respectability. But when his new neighbor, Frank Bellarosa — a powerful Mafia don under federal indictment — moves into the grand estate next door, Sutter’s world begins to unravel. Drawn into Bellarosa’s orbit of charm and danger, John and his wife, Susan, find themselves entangled in moral temptation, corruption, and betrayal. As loyalty collides with desire, The Gold Coast unfolds into a story of class, crime, and the slow seduction of power that threatens to destroy everything Sutter holds sacred.