A Dying Fall by Elly Griffiths

Rating: WARTY!

Another amateur meddler: "When archaeologist Ruth Galloway hears of an old friend’s sudden death in a house fire," she considers herself eminently qualifed to solve this, and summarily tells the arson investigator to fuck off. "...she works to uncover the truth behind his demise" which turns out to be smoke inhalation. The guy had heard it was a crack house, so he set fire to it and tried to inhale. "...and the recent discovery that made him fear for his life" which was that his smoke alarm wasn't working. Solved.