On the 17th of July, 1851, a tragedy of no little interest occurred in one of the residences of the Colonnade in Lafayette Place. Mr. Hasbrouck, a well-known and highly respected citizen, was attacked in his room by an unknown assailant, and shot dead before assistance could reach him. His murderer escaped, and the problem offered to the police was, how to identify this person who, by some happy chance or by the exercise of the most remarkable forethought, had left no traces behind him, or any clue by which he could be followed.