Cards on the Table

Mr Shaitana has the most unusual hobby: he collects criminals who have evaded justice.
Among his dinner guests are four suspected murderers. And, to match them, four experts in crime, including Hercule Poirot.
To understand which of them went on to kill their host, Poirot must delve deep into the psychology of each suspect. Which of them has the mind of a cold-hearted killer?