Tobechi Onwuhara specialized in hitting home equity lines of credit (HELOCs), the reservoirs of cash that banks make available to homeowners. Once Onwuhara gained access to a HELOC, he could siphon out vast sums in seconds. His weapon was persuasion. It got him enough money to start building a colonnaded fortress in Nigeria; enough to gamble at the high-stakes tables in Vegas casinos all night. Even his accomplices appear not to have known how much he was really pulling down — not even his beautiful fiancée, Precious Matthews.