There are various methods of inquiry. These methods can be grouped into either scientific or non scientific methods. The preferred method of inquiry in criminal investigation is the scientific method. In this method, an investigator develops a hypothesis and then investigates the viability of the hypothesis, which is a similar procedure as used in science. In addition to the scientific method of inquiry, non-scientific methods are also used. The non scientific methods relate to authority, tenacity and intuition. Authority method of inquiry is where an investigator takes the words of a person in authority as true and relies on them for investigation (Wood, 1995). In criminal investigation, authority method of inquiry can apply where an investigator is influenced by individuals in authority in his or her investigation. For example, claims from senior police officers may influence the direction of an investigation. Tenacity is the other method of inquiry. In this method, an investigator relies on prior knowledge without questioning whether the information is true or not. In criminal investigation, tenacity can lead to bias in investigation. For example, when investigating a crime such as drug trafficking, prior knowledge of the common trend in drug trafficking may mislead the investigation. Intuition is the other common method of inquiry. In this method, an investigator uses inner feeling to direct the investigation. In criminal investigation, some investigators claim to use inner feeling to direct their investigation but the method is not reliable. To be successful, an investigator should have the right mindset. This means that he or she should not have a fixed mind while carrying out an investigation but should be open to all possibilities (Ray, 1998). Despite being open to all eventualities, an investigator should be guided by the obvious and then move to the details. It is expected that a good investigator should have a checklist, which he or she uses as a guide in an investigation. The mindset in investigation usually is derived from experience, training, observation and studies carried out on a subject. The mindset provides an investigator with a framework which he or she uses to carry out investigations. Experience is vital in criminal investigation. Experience exposes an investigator to many possibilities and therefore helps make an appropriate decision at the right time. Therefore, being open to all possibilities is equivalent to having an investigative mindset. The following scenario illustrates the importance of being open to all possibilities: A man crosses the border regularly on bicycle. An investigator initially suspects the man to be a drug trafficker but on checking, nothing suspicious is found on the man. Later, the man is found to be smuggling the bicycle he was ridding (Ray, 1998, p.4). The scenario shows the importance of considering many possibilities rather than having a fixed mindset. The scientific technique is the most reliable method of inquiry. It is also possibly the most common method. Scientific method is a logical method of carrying out an investigation. Unlike non scientific methods, the scientific method follows a specific procedure in finding an answer to a given problem (Hunter & Dantzker, 2006). The s