In the face of these awkward alternatives, Merrington pursued the quest for Nepcote with vigour. The men working immediately under his instructions were spurred into an excess of energy which brought about the detention of several young men who could not adequately explain themselves or their right to liberty in the great city of London. But none of these captures turned out to be Nepcote. Merrington believed he was hiding in London, but at the end of five days he still remained mysteriously at liberty in spite of the constant search for him. He seemed to have disappeared as completely as though he had passed out of the world and merged his identity into a chiselled name and a banal aspiration on a tombstone. In the angry consciousness of failure, Merrington was not blind to the fact that he had only his own impetuosity to blame for allowing Nepcote to slip through his fingers. His mistake was due to his dislike of private detectives and his unbelief in modern deductive methods of crime solution. His own system, which is the system of Scotland Yard, was based on motive and knowledge. If he found a strong motive for a crime he searched for the person to whom it pointed. If there was no apparent motive he fell back on his great knowledge of the underworld and its denizens to fit a criminal to the crime. The system has its measure of success, as the records of Scotland Yard attest. Merrington had brought both methods to bear in his handling of the Heredith case. When his original investigations failed to reveal a motive for the murder, he determined to return to London to ascertain what dangerous criminals were at liberty who might have committed the murder. His own view then was that the murder was the work of an old hand who had entered the moat-house to commit burglary, and had murdered Mrs. Heredith to escape identification. The isolation of the moat-house, the presence of guests with valuable jewels, the time chosen for the crime, and the scream of the victim, tended to confirm him in this belief. Caldew's chance discovery about Hazel Rath, and the subsequent events which arrayed such strong circumstantial evidence against her, brought the other side of the system uppermost and set Merrington seeking for a motive which would accord with the presumption of the girl's guilt. Having found that motive, he was satisfied that he had done his duty, and he thought very little more about the case.