Terry Clane Series / The Case of the Backward Mule / Erle Stanley Gardner

To baffle the lie-detector clamped on his arm, Terry Clane used the technique of intense concentration that he had learnt in the Orient. But the sight of a little Chinese figure – an old man riding backwards on a mule – sent the lie-detector needle leaping: for he had given it once to Cynthia, his former fiancee and a close friend of a man convicted of murder who had escaped. “Either there is something which I have not accurately diagnosed,’ said the police examiner, ‘or else… you murdered Horace Farnsworth.”

That was just the start of a long and spine-chilling game of hide-and-seek played through San Francisco’s Chinatown.