Abstract
This paper deals with subsidiary prosecution, which is an institute that is not known to the current Czech criminal trial, but its legislative embedment is considered in the future. Attention is paid in this context, among other things, to criminal-law relations, which are applied through criminal-trial relations, and to the right to efficient investigation which the aggrieved party (victim of the crime) has in relation to the state.
The author admits, under certain conditions, the existence of subsidiary prosecution because it is a suitable form of how to check the principle of legality, as well as a suitable instrument against misuse of discretionary powers of the public prosecutor (in the systems built upon the principle of opportunity).