It need not be told in detail how Mike kept on the track of the other cab. Suffice it that when it turned into Fifth Avenue and kept on downtown, Chick was in time to see the two men go into the house next door to Anderton’s, and that he recognized one of them as Professor Tolo, while the other wore the blue blouse and wide trousers of a Chinese laundryman. “You can go now, Mike,” he whispered to Donovan. “If you stayed around, they might see you and be suspicious. Besides, I can handle this case myself now.” “An’ don’t I git no chance for a scrap?” demanded Mike, much disappointed. “Sure, I’d loike to let droive just wance at wan av thim there chinks. Yez tould me Oi w’u’d.” “I know I did, Mike,” returned Chick soothingly. “But we can’t always have things the way we want them. Better luck next time.” He paid the sum the taximeter showed, and gave Mike a generous tip in addition. Then he waved his hand in farewell and stepped into the deep doorway of the Anderton house, waiting there until Mike Donovan’s taxicab had been swallowed up in the gloom. It did not take Chick as long to get Ruggins to the front door as he had feared it would. The fact was that the butler had been so disturbed by all that had taken place that night and morning in the usually peaceful home that he could not sleep. So, when the night bell, which rang in Ruggins’ bedroom at the back of the hall, sounded, he heard it immediately. “‘Ello!” he grunted. “‘Ere’s more of it. I’m blowed if I ever was in a game like this ’ere before. What is it now?” He slipped into some of his clothing, and, with his suspenders hanging down, cautiously opened the front door a little way and peeped out. He recognized Chick at once. “W’y, Mr. Carter! Is there anything else wrong?” “Not that I know of,” replied Chick, as he pushed his way in and closed the door. “But I want to go up to Mr. Anderton’s study again. Don’t say a word to anybody.” “Do you mean you’re going to find out who murdered Mr. Anderton?” “I’m trying to do so. You can go to bed again. I will stay up in that room for the rest of the night. Mr. Anderton has some valuable things there, and if a man could get in to kill him, there is nothing to prevent his coming back if he wants to. Don’t ask any more questions, please, Ruggins. Mr. Carter told you to let me go where I pleased in the house, didn’t he?” “Yes. But I didn’t know you were coming back at this time in the morning,” protested Ruggins, in a doubtful tone. “Still----” “Still,” interrupted Chick. “I want to do it, because I believe it may help me to find out something. That’s all.” Leaving Ruggins to return to bed--or to sit up, if it suited him, Chick went up to the study and shut himself in. Then, without turning on the light anywhere, he stole cautiously to one of the windows and cautiously peered between the thick curtains. Instantly he dropped the curtains into place again and set his mind busily to work to decide on a hiding place in the room.