Most people were on their guard against detectives, who too often took advantage of their position to assume offensive airs of intimidation, whereas the great thing was to disarm suspicion by a friendly manner.

Barrant had cultivated pleasantness with considerable success.

Some who were not good judges of physiognomy were apt to overlook the watchful eyes in his smiling affable presence, and talk freely--sometimes too freely, as they later on discovered to their cost.

A chance word, a significant phrase, was sufficient to set him burrowing underground with the activity of a mole, to burst into the open later on with all his clues complete, to the confusion of the trusting person with an unguarded tongue.
He had put these tactics into execution with Austin Turold.

Austin, taking tea when he called, in a bright blue room hung with pictures, had received his visitor with a charming cordiality, insisted on his taking tea with him, and then let loose a flood of small-talk, as though he were delighted with his visitor.