(Source: A Day by Day Chronology of Mr. Sherlock Holmes according to Zeisler and Christ, compiled by William S Dorn.)
July 3, 1895: At 2 a.m., Patrick Cairns killed Peter Carey with a harpoon. [BLAC]
And there in the middle of it was the man himself, his face twisted like a lost soul in torment, and his great brindled beard stuck upwards in his agony. Right through his broad breast a steel harpoon had been driven, and it had sunk deep into the wood of the wall behind him. He was pinned like a beetle on a card. Of course, he was quite dead, and had been so from the instant that he uttered that last yell of agony.