“Was there any trace of him?”

“There was a stain or two on the rear cushions of the car, but nothing serious, so if he was wounded last night, I don’t think we need to worry about that.”

“But the tidal basin? Does that mean——?”

Though Bob left the question unfinished, the lieutenant guessed what he feared and was quick to ease his mind.

“I’m sure your uncle is still a captive. We’ve learned that sometime late in the night a high-speed motor boat dashed out of the basin and down the Potomac. It was a strange boat that came up the river early in the evening. We’ve a fairly good description of the craft and may be able to trace it down. Now our first mission is to locate your uncle and recover that paper.”

Bob liked the manner in which Lieutenant Gibbons spoke. The intelligence officer looked keen and alive to everything. He was a little taller than Bob and slender with a slenderness that was wiry. His eyes were a sparkling brown and there was an upward twist to his lips that Bob liked.

“Have you heard whether Condon Adams and Tully Ross have turned up anything?” asked Bob.

A frown marred the lieutenant’s forehead.

“They’ve been busy,” he said. “As a matter of fact, they’ve caused the arrest of Arthur Jacobs. They found some rather suspicious looking things at his apartment, including some half burned scraps of paper in a fireplace in which someone was offering Jacobs $5,000 for information on the radio secrets.”

“Does it look like a real lead?” Bob was anxious.