The Phantom is actually Richard Curtis Van Loan, a world-famous detective, whose true identity is only known by one man—Frank Havens.
"The lonely shack stood in the chill night gloom, its windows faint squares of light. Thin mist, driven by a wind which shook the dark branches of surrounding heavy trees, swirled coldly about the small, solitary building. Within it, under the glare of a single naked ceiling bulb, two men stood with their backs to the bolted oak door. They were watching a third man who crouched across the room before the gleaming dials of a small but full equipped short-wave radio apparatus."