All a burglar needs is a piece of putty and a diamond-cutter to break in." "But the curious thing is," continued Miss Cornelia, "that whoever got into the house evidently had a key to that door." Again she indicated the terrace door, but Anderson did not seem to be listening to her.
"Hello--what's this ?" he said sharply, his eye lighting on the broken glass below the shattered French window.

He picked up a piece of glass and examined it.
Dale cleared her throat.

"It was broken from the outside a few minutes ago," she said.
"The outside ?" Instantly the detective had pulled aside a blind and was staring out into the darkness.
"Yes.

And then that letter was thrown in." She pointed to the threatening missive on the center table.
Anderson picked it up, glanced through it, laid it down.

All his movements were quick and sure--each executed with the minimum expense of effort.
"H'm," he said in a calm voice that held a glint of humor.