Offences are related either when they have been committed at the same time by several persons together, or when they have been committed by different persons, even at different times and in different places, but as a result of a concert formed in advance between them, or when the guilty parties have committed some of them in order to obtain the means to commit the others, to facilitate them, to consummate their execution or to ensure their impunity, or when things taken, embezzled or obtained with the help of a crime or misdemeanour have been, in whole or in part, concealed.