consideration of the problem from the scientific-historical point of view had allowed to define the present state and prospects of development of the investigation departments. With the help of the law-psychological analysis of legislative acts which regulate activity of the investigator, some objective factors which make direct influence on a level of efficiency of his activity were allocated.
The experimental study of the given problem had allowed to empirically confirm influence of the organizational-legal factors on a level of professional successfulness of investigators, to define the attitude of the investigators to their work, and also to allocate the basic individual-psychological conditions of efficiency of investigation activity. The received data had allowed to develop a “professional portrait" of the investigator who is distinguished by a high level of efficiency of professional activity. The Professional portrait" represents the prognostic model of successfulness of professional activity of the investigator.
Key words: efficiency of professional activity, criterion of efficiency of professional activity, condition of efficiency of professional activity of investigators, professional-psychological training of investigators, professional successfulness of investigators.