These, of course, seemed to the Yard the essential clue, and we set to work.

Even in moment of passing, his dying hand would seek to leave behind essential clue.

Slippers were essential clue in one case, long ago.

They appear to be again the essential clue.

The essential clue was placed on scene by hand now dead.

The essential clue, which fell from his dying hand to lie at his side on the dusty floor.

He sought to present us with essential clue - what a man he was!

Field tests with these teachers and their students provided essential clues for the direction of the development.

And there, unless I'm a long way off the mark, you have the essential clue.

Perhaps the essential clue to dramatisation was given in the discovery that new born babies enjoy solving problems.