The investigation of a crime by a person not officially qualified, such as a policeman.(verb)
Investigation, in general.(verb)
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Use "sleuthing" in a sentence
"Genevieve's main sleuthing consists of a keen sense of smell which she uses to sniff out the trail of the missing cards."
"Although the amateur sleuthing is kept more as a backdrop than usual (see CRIMSON SNOW) to the vivid look at 1904 Indiana, fans of the series will enjoy the escapades and trials of Mrs. Cavanaugh."
"Our edition of Arturo Perez-Reverte’s seminal novel of book sleuthing is printed in two colors throughout, with nearly twenty original chapter head illustrations, a number of full-color plates, and a “hidden” image on the back of the dust jacket."