Whether it’s an assault, a burglary or a murder police investigation is the systematic process that law enforcement officers use to gather facts and evidence, interview suspects and witnesses, and solve crimes. A criminal investigation can include many modern scientific techniques, including forensic science, DNA examinations and fingerprinting. Investigators also use a range of investigative tools, such as crime-scene analysis and interrogation techniques. The criminal-investigation process ensures that evidence is collected and preserved, allowing for a thorough and fair trial.
Forensic investigations can involve examining all kinds of physical evidence, such as blood, hair, clothing, food and chemicals. Often this involves the use of sophisticated instruments, such as an electron microscope, to analyse biological samples or to identify chemicals in the blood. Other types of forensic science can help identify fingerprints, voiceprints and even DNA in bodily fluids such as urine and saliva. The use of a voice-recognition software, known as a voiceprint analyzer, can also help police identify suspects. In addition, a number of standard lab-based techniques can assist in identifying suspects and determining what happened, such as photographic and photomicrographic analysis, ballistics, chemical tests on bodily fluids, blood typing and other biological tests, and document examination.
If you witness or experience a crime get to safety and call 911 immediately. Try to remain calm and provide as much detail about the incident as possible. Police investigating the incident will ask you a series of questions about what you saw and heard. You may be asked to tour the area and point out landmarks, or you may be shown CCTV images of the crime scene. You may also be offered a medical examination by a doctor engaged by the police.