Raising the dagger, the mysterious woman hissed:

"If you attempt to penetrate my identity, I shall stab you!"

There was a ring of intense earnestness to her voice, and it froze the
smile that rose to the old detective's face.

He regarded her with a puzzled look.

It now began to dawn upon his mind that she was not Mrs. La Croix after
all. The voice was different. She was shorter and stouter than the
smuggler's wife. Her actions were different.

To gain time to form a different tactic he exclaimed:

"How can you be a friend of mine if you are going to stab me?"

"I am bound to keep my identity a secret," she replied, firmly.

"What object have you in befriending me?"

"You are a brave man and a dutiful officer. I know you are only following
up this case because you were ordered to do so. I therefore don't wish to
see you perish."

"How do you know I'm doomed to get killed?"

"Because I heard your enemies plot your destruction."