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Chain Of Custody


Define Chain of Custody (COC)

Chain of custody (COC) is a legal term that refers to the ability to guarantee the identity and integrity of the evidence from collection through to reporting of the test results. It also refers to the document or paper trail, showing the recovery, custody, control, transfer, analysis and disposition of evidence. Strict observance of the legal COC in specimens obtained is mandatory to guarantee the reliability and integrity of the analysis. Properly recognized, obtained, packaged, transmitted, analyzed and stored specimens facilitate the admissibility of results and valid expert interpretation in the court of law (Lyle 2004). Under Evidence Act 1950, COC is also defined as the witnessed, written records of all the individuals who maintained unbroken control over the items of evidence.

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Integrity of Chain of Custody

Specimens collected from National Institute of Forensic Medicine, Malaysia are divided into forensic pathology samples, including autopsy and evidences collected at scene of crime and clinical forensic medicine samples, including specimens from victims, suspects or arrested persons and DNA evidences collected for paternity or maternity disputes. These specimens are taken to support postmortem findings on victim or perpetrator, to determine their manner or cause of death and act as evidence to relate or convict suspect to the crime. These specimens are sent for analysis including toxicology, alcohol, DNA and serology, entomology, weapon / tool mark, ballistic, physical trace evidence, histopathology, microbiology and virology testings.

Source: practicalhomicide.com

Source: mass.gov

How To Maintain COC

Chronology of documentation

Documentation starts from the receiving of a communication calls while sitting in the forensic service office at police station, but never stops or ongoing till when the investigation is completed and the case is closed. Documentation is the most important steps that requires investigator to be most systematic and organized in their procedures to record and preserve the location and relationship of physical evidence and condition of crime scene or the body found as well as to allow for any subsequent re-evaluation of the scene or physical evidence found at scene or the body itself. There are five documentation methods including note taking, still photography, sketching, videotaping and audio-taping. Notes are one of the components for the written record of activities, location of physical evidence, description of people at scene, condition of crime scene and autopsy findings. Audio and video tapings are essentially another form of note taking. Sketches and photographs complement each other to depict the crime scene or victim’s injuries adequately and properly. The well-worn saying one picture is worth a thousand words. Photographs aid in refreshing the memories of witnesses and investigators and show the relationships of items of evidence at the crime scene as well as help to convey an images or circumstances of crime or victims to the jury. For a photograph to be admissible in court, the investigator must be able to testify that it accurately depicts the area shown (PDRM 2009).

Movement and location of evidence

Whoever finds an item of evidence, it has to be marked with initials for later identification, but not to damage or alter any of the specific identifying characteristics. This is to ensure the investigator or pathologist can positively identify evidence as the exact one they found at the scene or body. However, not all evidence can be marked directly like bullet or shell casing, it can be placed into an evidence bag which is initialed by the person’s name who finds it and marked with information including the case number, the name and description of the item, the name of any witnesses to the discovery and recovery, date, time as well as location of the find. Some items require special packaging before being placed in an evidence bag. For example, a blood sample may be taken by pathologist using a moist cotton-tipped swab. After drying, the swab is placed into a sealed glass tube, and the tube is then marked with the collector’s initial and date. The tube is finally placed into an evidence bag which is similarly marked (Lyle 2004).

Personnel & Agency Involved

Each officer, who accepts an item of evidence, signs and dates the evidence bag and is then responsible for maintaining its integrity until it is passed along to the next officer or through the link in a chain. For instance, a police officer finds a shell casing at the scene of a homicide; he collects it, marks it, places it into a marked evidence bag and then signs it over to the crime-scene investigators. The investigator transports the evidence to the lab and signs it over to the forensic scientific officer (FSO) and continuous COC is maintained at the lab as more exhibits may be generated than actually come in. FSO packs the generated exhibits separately and give identification of their own with full description of the samples on note book or work sheet in order to be easily recognized by signature on label. After the item is tested and evaluated, the FSO signs the evidence over the police department’s custodian of evidence likewise involving the officer in charge of the secured evidence lock-up area at the police station. The custodian of evidence places the evidence in a secured area until it’s needed again. From there, it may be signed over to the prosecuting attorney for presentation in court (Lyle 2004). It is same goes to the specimens collected at the forensic medicine department by the forensic pathologist or medical officer.


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Source: crimefictioncollective.com

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Chronology of documentation and movement of evidence


What Is Importance of COC in Court of Law

According to Oxford English Dictionary, exhibits are any document or object produced in court and referred to and identified in evidence. Evidence is all legal means exclusive of mere argument that tends to prove or disprove the truth of the subject under judicial examination. Continuity of the evidence is a documentary proof that an exhibit has been conducted from a locus or a person usually by series of steps and sometimes involving the scientists to the court of law for the purpose of a trial. Without a continuous record showing that evidence has been kept safe and secure from the crime scene or mortuary to the lab and ultimately the courtroom, evidence may be rendered inadmissible in court. Any defense attorney worth their salt would rightly question the authenticity and integrity of any evidence for which outside contamination cannot be ruled out. That’s why every person who handles the evidence must be accounted for and recorded as a link in this unbroken COC, from crime scene to courtroom. If the COC remains intact, each witness, from the officer who found it to the custodian of evidence, can testify that the item presented in the courtroom is indeed the item that was collected at the scene or mortuary and tested by the lab (Lyle 2004). It is vital that crime scene investigation is properly managed to ensure all the exhibits submitted to court are admissible. Evidence recognition, collection and preservation at the primary scene are crucial to get a quality result analyses through field test devices (Almog 2006).

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Chronology of Chain of Custody

All of all, the preservation is the very importance of COC in court of law. This is to prevent the change of the original condition or the disturbance by adding, removing, moving, destroying or cross-contamination of the evidences at scene. Some of the preservation including always put on gloves and masks when entering the crime scene or mortuary, use of clean tools and equipments, pack and seal or double-seal exhibit correctly, examine the victim and suspect at specific site such as mortuary or forensic medicine department away from crime scene. Preservation starts from the proper recording at scene likewise documentation, tagging, seal and label, notes, sketches, photography or video footage. Whilst recovery is the collection and packaging of physical evidence in a way that prevents any change from taking place between the times it is removed from the crime scene and the times it is received by the forensic laboratory (Saferstein 2007). Proper tagging and labeling of physical evidence for later identification is important in adding credibility and control to the ability to identify the items in future. Often time people do not understand the importance of the little things that they do until they have done them. It is the little things that make people stand out. Do not speak of the work; however allow the work to speak for the people (PDRM 2009).

Source: mlive.com
Examination of evidence in the laboratory

Impact Of COC Towards The Value Of Evidence And The Trial’s Outcome

Under Section 60(3) of Evidence Act 1950, if oral evidence refers to the existence or condition of any material thing including a document, the court may, if it thinks fit, require the production of that material thing or the document for its inspection. Value of evidence should be kept in mind by the investigator or pathologist when doing the crime scene investigation or autopsy. Forensic science does not start in the laboratory but at the crime scene and body found (Almog 2006). All physical evidence should be carefully packaged and marked at the crime scene. Care must be taken not to destroy evidential value or restrict the number of examinations possible. Name and signature of collector and date should be inscribed onto the packaging along with a description of item and where it came from. Transfer of evidence between individuals must be recorded in notes and appropriate forms. Every individual who possess that evidence must maintain a written record of acquisition and disposition. Failure to substantiate the evidence’s COC may lead to serious questions regarding the authenticity and integrity of the evidence and examinations of it. Integrity refers to the exhibit is a guarantee that it has not been tampered with or altered from its original state. Integrity if maintained by proper packaging, labelling and signature ensuring there is no gap in continuity and not been compromised, for instance, by cross-contamination. Preserve the continuity of the COC and distinct identity of the evidence through proper packing, labelling, sealing and observing other legal formalities. The possession of the evidence should be accounted for from the time of its recovery at scene to the time of its production in court (PDRM 2009).

Oral Evidence

For example, the ability to perform successful DNA analysis on biological evidence recovered from a crime scene or body depends very much on what kinds of specimens were collected and how were they preserved. If it is not properly collected, its biological activity may be lost. If it is improperly packaged, cross contamination might occur. And if the DNA evidence is not properly preserved, decomposition and deterioration may well occur. And of these effects will seriously affect the outcome of DNA typing and subsequently the trials. The unsatisfactory handling of the sample of blood leaves so many material gaps. The accused therefore cannot be penalized for the lack of ingenuity and seriousness in the police investigation and the conduct of the prosecution and he is entitled to the time-honored benefit of doubt (see Pang Chee Meng v Public Prosecutor [1992] 1 MLJ 137 at p 142). If the prosecution wish to rely on DNA evidence to establish a link between the sample of blood and the suspect in the instant case, against the accused, the prosecution ought to have at least introduced the basic set of facts to show who took the sample of blood, information such as from whom, how and when until such evidence is produced by the prosecution (Hisyam Abullah 2008).

In a nutshell because evidences can be used in court to convict persons of crimes, it must be handled in a scrupulously careful manner to avoid later allegations of tampering or misconduct which can compromise the case of the prosecution towards acquittal or to overturning a guilty verdict upon appeal (Lyle 2004).



  1. Almog J. 2006. The Concept of Diagnostic Field Tests. Journal of Forensic Science. S1(6) 1228 – 1234.
  2. Evidence Act 1950. Law of Malaysia: Incorporating all amendments up to 1 January 2006.
  3. Hisyam Abdullah @ Teh Poh Teik. 2008. Criminal Trial Advocacy For The Defence. 1st Ed. Pg. 221 – 233. Selangor Bar’s Secretariat.
  4. Lyle, D.P. 2004. Working the scene: Evidence Collection and Protection. 1st Ed. Forensic for Dummies  pg. 29 – 46. Indiana: Wiley Publishing Inc.
  5. PDRM Forensic Laboratory. 2009. Chain of Custody. National University of Malaysia NX 3014 Crime Scne Investigation.
  6. PDRM Forensic Laboratory. 2009. Contamination & Preservation of Evidence. National University of Malaysia NX 3014 Crime Scne Investigation.
  7. Saferstein R. 2005. Criminalistics: An Introduction to Forensic Science. 8th Ed. Prentice Hall.


Last Reviewed : 23 August 2019
Writer : Lai Poh Soon
Accreditor : Dr. Siew Sheue Feng
Reviewer : Dr. Khoo Lay See