"Yes, it's hardly the kind of thing a barge watchman would wear," commented Foyle. "We'd better take the bag along, and you can go through it at your leisure. The laundry marks will tell whose they are. You had better stop here, Wrington, and take charge. Find out whom the barge belongs to, and make what inquiries you can. Better have it thoroughly searched, and report to me in the morning. Use your discretion in detaining any one who comes aboard."

One of the motor-boats took Foyle and Green back to Scotland Yard. Both were glum and silent: Foyle because his plan had miscarried at the very moment that he had reached the keystone of the problem; Green because it was his natural habit. It was easy enough to realise now that the whole question was one of light. Had some one thought to strike a match while the struggle was going on there would have been no confusion, and the man would have been unable to get away.

Nor did the news that awaited Foyle at his office tend to make him more pleased with the progress of the investigation. A telephone message had come

through the chief of the Liverpool detective force—

"Man found drugged in first-class compartment of express from London, bears warrant card and other documents identifying him as Inspector Robert Blake, C.I.D., London. Is now under care of our surgeon, and has not yet recovered consciousness. In no danger. He travelled from London with a woman fashionably dressed, dark hair, dark blue eyes. Am now endeavouring to find her. Can you suggest any steps we can take?"

Foyle banged his fist viciously on his desk. "There! We're not the only people who have made blunders to-day, Green. Look at that. Wire to them a full description of this woman Petrovska, and tell 'em to detain her if they come across her. We charge her with administering a noxious drug, and that'll hold her safe till we get the business cleared up. If she's trying to slip out of the country, they're pretty safe to get her in one of the liners. Wire over our men at Liverpool to the same effect."

Green slipped away. In a little he returned with a slip of paper in his hand. "Wire's gone to Liverpool. I've drafted this out for Mr. Jerrold, if you'll just look at it. I promised him he should know anything there was to tell."

The sheet of paper read—

"In connection with the investigation into the murder of Mr. Robert Grell, Superintendent Heldon Foyle, accompanied by Chief Detective-Inspector Green, Divisional Detective-Inspector Wrington, and other detectives, examined the body of a man found in the river, whom it was supposed might be the man Goldenburg, for whom search is being made. The police are of the opinion that the drowned man is not Goldenburg."

A light of amusement twinkled in Foyle's blue eyes.