Up until several decades ago, forensic evidence was regarded as a set of well-established and trusted methods, and in many legal systems was even considered to be incontestable. The emergence of DNA analysis, together with changes in the law and advances in the broader scientific community, led to a serious questioning of the validity of many of the traditional forensic disciplines, and revealed errors made in both forensics and the legal system. First, there is potential bias in choosing the shoeprints according to the suspect’s shoes: in cases of arresting the suspect prior to searching the crime scene, the Crime Scene Investigators occasionally observes the suspect’s shoes and then focuses on the matching shoeprints at the crime scene. Contextual bias may occur if the examiner is exposed to irrelevant information about the facts of the case (such as information about prior convictions) which could influence his/her judgment, especially in the determining the strength of the conclusion.