"How do you know that?" asked Galloway.
"Because he was watching Benson from the window."
Galloway looked startled.
"You go too deep for me," he said. "Was it Penreath who got out of the window?"
"No, Penreath, like Benson, was the victim of a deep and subtle villain."
"Then who was it?"
Before Colwyn could reply a shriek rang out—a single hoarse and horrible cry, which went reverberating and echoing over the marshes, rising to a piercing intensity at its highest note, and then ceasing suddenly. In the hush that ensued the chief constable looked nervously at Colwyn.
"It came from the rise," he said in a voice barely raised above a whisper. "Do you think——"
Colwyn read the unspoken thought in his mind.
"I'll go and see what it was," he said briefly.