An investigation is undertaken when a crime has been reported and a police officer investigates the circumstance following all lines of enquiry of the situation to determine if a crime has been conducted and where a person/s should be charged with an offence, or if the person who offended is guilty.

Under the Home Office counting rules, when members of the public are making a complaint, victims should be believed for the matter of recording a crime unless it's clear that the incident did not happen. An investigators duty is to gather and test all material presented including witness accounts/statements and use technical and scientific expertise to maximise evidential opportunity.

The following outcomes may be that the suspect is prosecuted in court, receives an out of court disposal, community resolution or charges dropped. A lot of the times investigators may not find enough evidential material to make a charging decision either as a result of lack of evidence or not enough lines of enquiry to pursue. However the investigation outcome must still be recorded accurately for intelligence purposes and especially for future use, as this will help police identify crime hotspots and help reduce crime rates.