Main characters
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| Sherlock Holmes An intelligent, patient and a good detective from Baker Street, London |
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| Dr. Watson A good sidekick who helps Holmes to solve cases |
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| James McCarthy An innocent victim blamed to have killed his own father |
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| John Turner The murderer who was blackmailed by the victim |
Minor characters
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| Charles McCarthy The victim |
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| Alice Turner John Turner's daughter |
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| Insp Lestrade The police officer who did the first investigation |
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| Patience Moran A 14-year-old girl, the daughter of the Gamekeeper who saw James and Charles McCarthy having an arguement |
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| Mrs. Moran The person, whom Patience related the argument she saw |
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| The judge The person who sentences James to prison |
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| The Gamekeeper (Moran) One of the witnesses who saw James and Charles on the path to Boscombe Pool |