Photo from the personal archive of S.S. Podushkin

A properly trained dog, when choosing, indicates her choice by barking or lightly grabbing the hem of the clothing the person whose scent is uniform with the scent of the thing, object or trace.
When choosing a criminal from a group of people, the dog must be able to freely pass each individual. If necessary, the selection is divided into groups of 10-12 people.
Only systematically trained, well-prepared dogs are allowed to choose a criminal from a trail or an item.