The author discusses in this article the rules of investigation of the flagrant crimes. To apply a special procedure in such cases is not only a theoretical but and a practical value. It’s very important to realize that the exception to general procedure want to discover a illegal acts in no time and with maximum effects so to simplify the justice. Unfortunately, there are the cases when the law institutions find out this methods and recommendations more as the impediments which make the proofs difficult to be collected. It’s an unfair opinion which must be changed with scientific arguments. There are also several uncertain regulations in our criminal procedure which have to be explained. Only an impeccable criminal investigation in this cases lead to a fast and complete results.