A moment later they were off across the field and soon came to the woods which sheltered the deserted house. In Indian file they commenced to pick their path among the trees and underbrush. Complete silence was maintained and the party advanced, ready for any emergency. Of course the detectives were armed. Mr. Cook carried his pistol, so Bob and Hugh were the only ones not provided with some means of defense. In the course of perhaps fifteen minutes Bob, from his position in the lead, caught a glimpse of the old house through the trees. So far as he could see there was no sign of life around it anywhere. He held up his hand and the little party came to a halt. A whispered consultation was held and it was decided to spread out somewhat and move forward in open order. The plan was to advance until they reached the border of the trees, and then at a given signal rush out into the opening and surround the house. Stealthily the band stole forward. The spring air was soft and balmy, the buds on the trees were commencing to swell; everywhere nature gave signs of a reawakening, but these things passed unnoticed. The members of the little party were occupied with the business in hand, and had no time or interest for anything else. Soon they reached their appointed positions. From the spot where he crouched Bob could see the others lurking within the shelter of the trees. He could see Sergeant Riley raising a police whistle to his lips to sound the signal that had been agreed upon. Bob set himself. He had been advised that inasmuch as he was unarmed he should remain behind, but he had no such intention. Neither had Hugh. Suddenly Sergeant Riley sounded a shrill blast with his whistle. Every man rushed forward. Only for a few steps, however. A burst of flame, and a puff of smoke shot from the cellar window of the old house, and the air was rent by a terrific explosion. CHAPTER XV FIRE Staggered, the men all stopped short in their tracks. An instant later there was a second explosion. There was a ripping, splitting sound, and the whole side of the building fell out. The air was filled with bits of wood and plaster. "Keep away from that house!" shouted Sergeant Riley as one of his men darted forward. "Do yez want to get killed?" A minute later flames appeared, and the red and yellow tongues of fire began to play around the window frames. Black smoke curled from every opening. It was plainly to be seen that the house was doomed. "Look!" cried Hugh suddenly. "There goes a man!"