This duty is engaged where the accused provides evidence of serious misconduct and identifies third party information that it believes is relevant to that serious misconduct this includes evidence of attempts to fabricate evidence. free pdf duty collection and use of criminal evidence uploaded by enid blyton duty collection and use of criminal evidence huang wei zhi lei jian chang zhang bin zhu on amazoncom free shipping on qualifying offers duty collection and use of criminal evidence the crown must preserve evidence on a close case for the purpose of disclosing it should charges arise there is a duty to preserve . Duty collection and use of criminal evidence huang wei zhi lei jian chang zhang bin zhu on amazoncom free shipping on qualifying offers duty collection and use of criminal evidence. The government has a duty to preserve certain types of evidence it collects during criminal investigations and prosecutions this duty exists in order to protect a defendants rights to due process and a fair trial under the sixth and 14 th amendments to the us constitution