Green’s Dictionary of Slang

to act as a detective; to deduce.

1913		V.Z. Post Diana Ardway 239: I sherlocked it out that one girl had happened in and seen the other one’s flowers and replaced them with her own.
1919		P.R. Cambell Diary 118: We scrambled through the underbrush and reached their little road, and Sherlocked our way home following their horses’ hoof-prints.
1921		C.N. Williamson Brightener 274: But almost at once I told myself that I ought to have Sherlocked the truth.
1935		‘Grey Owl’ Pilgrims of the Wild 247: And so ended the Mystery of the Murdered Muskrat, in which, for once, I rather out-sherlocked myself.
1951		Kerouac On the Road (The Orig. Scroll) (2007) 237: They tried some amateur Sherlocking by asking the same questions twice expecting us to make a slip.
1956		R. Christopher Ocean of Fire 230: When our men came up, it turned out I had been right; I had out-Sherlocked my policeman friend.
1999		T. Zahn Icarus Hunt 82: It certainly wouldn’t be the first time I had oh-so-cleverly Sherlocked myself straight down a blind alley.