Going back to the Red Gables case, careful reading of the newspaper article throws up more questions..
Late to this though I am, to return to Red Gables once more ... I also had a questions from the newspapers article though perhaps not as pertinent as Dave's.
One local states how regular the man is in his habits. "He would just have half a pint of Guinness and then go. He never stayed longer than half an hour. When we heard about all this on Friday night, no-one could believe it”.
And yet he had two gins that night, as well as a glass of Guinness. Very much not 'his normal self' - that's a pretty heavy half an hour, or an atypical prolonged stay.

Signs that something was up were certainly there, alas, only those with the advantage of foresight are likely to recognise their significance.