John Dickson Carr 
The Man Who Could Not Shudder [EPUB ebook] 

Three guests at Martin Clarke’s weekend party swore they saw the pistol lifted from the wall, levelled and shot. Yet no hand held it. It couldn’t have happened … but there was a dead body on the floor to prove that it had. For the victim, it was far too late for a doctor. To unmask the clever murderer, however, a house visit by Dr Gideon Fell is just what the doctor ordered. But the killer still somehow avoids taking his medicine — until Fell vows to prescribe his own remedy for bringing the murderer to justice.