The plot, according to the surroundings, could now be outlined. Preparations for the "removal" of the unfortunate physician had been commenced as early as February, when the flat was hired and the furniture purchased. Apparently it was the original intention to lure him into the third story of the Clark street building, where isolated, and, as "Simonds" remarked, "with no tenants on the same floor," he could be summoned from his office on the other side of the street and speedily done to death. For some reason or other, however, possibly because a single outcry might have alarmed the people on the floor below, this idea was abandoned, and the lonely cottage was hired. For over six weeks the assassins must have plotted and planned the carrying-out of their murderous intentions. Then came the summons of the night of May 4th, the crime, the efforts to dispose of the body in the lake, its concealment in the catch-basin, the throwing away of the bloody trunk, the endeavor to efface the blood-stains in the cottage with paint, and finally the strenuous effort to continue its occupancy, in order that its condition might not be seen by other eyes. So far the authorities were satisfied with the results accomplished. ICEMAN O'SULLIVAN SUSPECTED. The opinion was now almost general that Iceman O'Sullivan knew more concerning the tragedy than he was willing to admit. No one was yet bold enough to accuse him of actual complicity in the crime, while at the same time it was apparent that his statements to the police, as well as to the friends of Dr. Cronin, were widely at variance with the discoveries that had been made. The peculiar nature of the contract he was said to have made with the physician, to attend any man in his employ who might meet with an accident, his denial of any acquaintance with the men who had rented the cottage, in the face of the fact that he had been seen in conversation with "Frank Williams," and had guaranteed the payment of the rent by the latter, and numerous other circumstances, some more or less trivial, were sufficient to raise the question as to whether, even had he taken no actual part in the terrible crime, he, in legal phraseology was not "possessed of a guilty knowledge." Hence it was the police decided to place the iceman under surveillance. Thereafter his house, as well as his every movement, when out of doors, was watched both night and day, and any attempt to leave the city would have resulted in his immediate arrest. CHAPTER VIII. THE WHITE HORSE AND BUGGY--DETECTIVE COUGHLIN HIRES IT FOR A "FRIEND"-- THE TROUBLE IN THE STABLE--DINAN GOES TO SCHAACK--THE CAPTAIN'S PECULIAR MOVEMENTS--SCANLAN IDENTIFIES THE HORSE--THE DETECTIVE AND O'SULLIVAN ARE JAILED--THE GRAND JURY INDICTS THEM WITH WOODRUFF--FULL ON THE TRACK OF THE CONSPIRATORS. "Who owned the rig in which Dr. Cronin was driven to the assassin's den?"