The article presents basic approaches to object identification, system identification and stochastic approach in the field of criminology. The basic theorems of identification are the identity, the individuality of the objects and the relative stability of the objects. The system approach in identification research presents a new perspective and allows a wider view of criminal identification. Between the extreme borders of individual identification and determination of group membership, it is possible to narrow down the set of objects searched in some cases by calculating the probability level. The probability aspect creates a sort of "filter" that only passes objects that meet certain and defined conditions. The notion of stochastic, ie the probability of narrowing of group membership, appears in criminological literature in the past. The author deals with the stochastic approach and the determination of the boundary for a high probability level.