Sleuth is a fun, sometimes playful, word for "detective." As a verb, it's also what a detective does. When you seek clues, you sleuth. You, sleuth, you!
The word sleuth comes from the Old Norse sloth, meaning "trail" and sleuthing is following a trail. One type of bloodhound skilled at following trails is called a sleuthhound, and that word was shortened to sleuth in the late 19th Century, referring to an investigator. As an amateur sleuth, you caught the robber dressed as a mummy before the police did. He would have escaped if not for you, you meddling sleuth!