Chain of Custody


The most important aspect of evidence documentation is the chain of custody. It is essential to demonstrate to the court that the evidence is genuine, i.e., that it is the same evidence obtained at the crime scene. It was always in the possession of a person assigned to manage it, and it was never unaccounted for. It is necessary for proof to be admissible as evidence in court. The chain of custody or chain of evidence refers to the continuity of possession or custody of evidence, as well as its movement and location from the moment of discovery and retrieval through its transit to the laboratory for inspection and until it is authorised, acknowledged and admitted in court.

The prosecution presents the chain of custody documentation in court to establish that the item of evidence is, in fact, linked to the alleged crime and that it was in the defendant’s possession. In order to demonstrate a reasonable doubt of guilt, the defence searches for loopholes or violations in the chain of custody, for example, to indicate that the object was fraudulently “placed” to make the accused person appear guilty. To avoid all of these, an item of evidence must always be in the physical possession of an identified, legally-authorized person from the time it is collected until it presents in court.


The sequence and manner in which physical or electronic evidence in criminal and civil investigations has been handled, maintained and processed is referred to as the chain of custody.

Importance of the Chain of Custody

The chain of custody establishes the authenticity of a piece of evidence. A paper trail is kept so that the people in charge of the evidence at any one moment may be identified quickly and effectively and called to testify during the trial if necessary.

When submitting evidence as an exhibit, a record of the chain of custody must be kept and established in court. Otherwise, the evidence may be ruled inadmissible in court, raising severe concerns about its validity, integrity, and the examination conducted on it.

To avoid tampering, evidence must be handled with care. The chain of custody is defined as the sequential record or trail that accounts for the sequence of physical or electronic evidence custody, control, transfer, analysis, and disposition. The objective is to prove that the evidence is linked to the alleged crime, was gathered from the location, and was in its original/unaltered form rather than being tampered with or “placed” deceptively to make someone appear guilty. The sample’s integrity is protected by the chain of custody. The traceability of the record of sample control, transfer, and analysis demonstrates the procedure’s transparency.

• The identification and sign of each participant who handled the evidence and their duty to do so.

• The length of time each individual who handled the evidence had it.

• How the evidence was transferred each time it was passed from one person to another.

To the prosecution in criminal proceedings, a comprehensive and correctly filled Chain of Custody Form is crucial in withstanding legal objections to the legitimacy of the evidence.

Chain of Custody Form

The Chain of Custody Form (CCF or CoC) is used to document all changes in physical and electronic evidence seizure, custody, control, transfer, analysis, and disposition. A typical Chain of Custody Form will describe the evidence as well as the place and circumstances under which it was acquired. The CCF must be updated as the evidence progresses during the investigation and trial to indicate, at a minimum:

• The identification and sign of each participant who handled the evidence and their duty to do so.

{Note: Only identified individuals with permission to hold the evidence, such as police officers and detectives, forensic analysts, certain court officers, and evidence technicians, may handle the Chain of Custody Form.}

• How the evidence was transferred each time it was passed from one person to another.

• The length of time each individual who handled the evidence had it.


The chain of custody documentation serves three major purposes:

• To ask the analytical laboratory relevant questions about the evidence,

• To keep track of the chain of custody and verify that the sample/evidence was handled only by authorised people and was not tampered with before being analysed.

To track down the sample, the investigator or the person in charge of collecting evidence must fill out the labels on the sample container/bags and the chain of custody paperwork.

Each sample container label must have a unique identification code as well as other pertinent information such as the collection location, date, and time, the name and signature of the person who collected the sample, and the signature of the witness (es).

To minimise damage during shipment, the evidence must be properly packed and secured, ideally in tamper-evident/resistant bags or with tamper-evident tapes.

Different evidence bags must be accompanied by a separate chain of custody form. The following information must be included in the chain of custody form:

• Unique identifying code

• The sample collector’s signature and name

• Official contact information (address and phone number)

• Recipient’s full name

• The lab’s location

• Collection day and time

• Analyses to be performed

• Signatures of each individual involved in the chain of custody, along with the date and time.

• Delivery Method and timeframe

• Permission to conduct a sample analysis

• Any other information on the sample

Process of Custody of the Evidence

Data Collection: 

Data collection is the first step in the chain of custody procedure. It entails identification, labelling, recording, and the gathering of data from all the potential relevant sources that protect the integrity of the data and evidence acquired.


During this step, the chain of custody information is documented, as well as the forensic process that was carried out. It’s important to take photographs throughout the process to demonstrate the tasks that have been done and the evidence that has been discovered.


The result of the examination step is the analysis stage. In the Analysis stage, legally permissible procedures and techniques are utilised to gather valuable information in order to respond to the questions asked in the case.


This is the documentation step of the Examination and Analysis stage.

Other Cases of the Chain of Custody Usage

Other areas(but not limited to) where chain of custody maintenance is utilised, are:

• Civil litigation

• Legal Drug Testing

• Seizure of controlled/prohibited substance

• Testing of Food Products

• In clinical trials

• In Art forgery

• Supply chain integrity

• Seizer of Valuable items by Authorized Investigation Service

• In case of Violence

• In firearms injuries, etc.

Chain of Custody in Civil Cases

While a chain of custody is more often a matter in the criminal justice system, it may also be necessary in civil proceedings.

For example, Medical and hospital documents maintained in an unbroken chain of custody must be submitted as evidence in medical malpractice proceedings.

Chain of Custody in Legal Drug Testing

When testing for drugs of abuse with urine samples, it is essential that the donor/athlete/sportsperson identify the sample and that the pee cup is sealed (preferably by themselves). The donor/athlete should next sign the chain of custody documents, followed by the person who collected the samples.

A drug test in a clinical environment utilising urine or blood samples is typically required in cases of suspected overdose patients being brought to the emergency room. Typically, immunoassays are used to check urine samples for pharmaceuticals. On the clinician’s request, analytical procedures validate the preliminary results.

Chain of Custody – Digital Forensics

In digital cyber forensics, the chain of custody is also known as the paper trail, forensic link, or chronological documentation of the evidence. Digital evidence is gathered from a wide range of devices, including IoT devices, audio evidence, video recordings, pictures, and other data saved on hard drives, flash drives, and other physical media.


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