It was made of fine, heavy bristol board, and was the general shape of a visiting card such as a man might use. On the side which had undoubtedly borne the name and address were two oblong blurs showing where a knife had scraped out the names and numbers. On its reverse the card bore a stain of blood and these words, in pencil: “Quarter to twelve, Mechlin, Gotham.” “Here’s something, at all events,” thought Nick. He placed the card carefully in his pocketbook; then, with a final look at the spot where Gardner had had his life and death struggle, he started slowly and thoughtfully out of the alley and toward the front of the bank. Before he reached the bank entrance he came to a sudden halt. “By Jove!” he muttered. He did not go into the bank, at that moment, but hastened past the entrance and turned in at a telegraph office further down the street. There he wrote out and sent the following “rush” message, the contents being in cipher: “CHICKERING CARTER, New York: “Investigate No. 1145 Mechlin Street immediately. Send Patsy along by first train. NICK.” CHAPTER XVIII. A MYSTERIOUS BULLET. It was ten o’clock when Nick Carter walked into the People’s National Bank, halted at the cashier’s window, and asked for Mr. Hepner. The cashier knew all the customers of the institution, and the sight of a strange face prompted him to put a question on a matter that was uppermost in his mind: “Are you Mr.----” “Yes,” interrupted the detective. “I am Mr. Nicholas, the man you are looking for.” The cashier gave a start and looked at Nick blankly for a moment. Then his face cleared. “Ah, yes,” he smiled. “I understand. I will go in and tell Mr. Hepner you are here, Mr. Nicholas.” “Just a moment. I would like a look at the vault before I talk with Mr. Hepner.” “Very well, sir.” The cashier opened the door of the cage, and Nick stepped in, throwing a critical glance about him as he walked to the wrecked doors of the strong room. Brown soap lay thick on the edges of both doors. He passed inside the steel chamber, the cashier accompanying him. “Made a pretty clean sweep, did they?” Nick asked, looking keenly around at the evidence of pillage. “They seemed to know just what they wanted, Mr. Car--er--Mr. Nicholas.” “That’s a way they have--sometimes. Did they make off with any specie?” “Both specie and bills.” “I see. Now I believe I will talk with Mr. Hepner.” The cashier took the detective to the president’s door and announced him. “When did you get in, Mr. Carter?” asked the president, after greeting his caller. “I would prefer to have you allude to me as Nicholas, Mr. Hepner. Cut out the Carter, for the present.” “All right, Mr. Nicholas. When did you reach town?” “Last night.” “I have been looking for you to call for two hours or more.” “I was too busy to call before. Just how much more than five thousand dollars did the thieves make way with, Mr. Hepner?”