If the owner or keeper does not submit his sample intact within the time limit set by the examining magistrate, the sample is no longer taken into account. In this case, the two experts are assigned to examine a single sample. When, in the course of or as a result of their investigations, the experts are led to presume that a substitution of samples has been made, they are obliged to inform the investigating judge immediately and to make available to the judge any exhibits likely to reveal the substitution.