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In criminal and civil law, the term “chain of custody” refers to the order in which evidence has been handled during the investigation of a case. It is necessary to demonstrate that any object or element that is considered as evidence, is handled correctly through an unbroken chain of custody so that it can legally be presented in court. Though often unnoticed outside of court, proper chain of custody has been a crucial factor in high-profile cases, such as the 1994 murder trial of former professional football star OJ Simpson, who was charged with the murder of his wife. Nicole Brown and her friend, Ronald Goldman.
Key points about the chain of custody
- Chain of custody is a legal term that refers to the order and manner in which physical or electronic evidence has been handled in criminal and civil investigations.
- In criminal trials, the prosecution must generally show that all evidence was handled in accordance with a properly documented, unbroken chain of custody.
- Evidence related to the crime that has not followed an unbroken and properly documented chain of custody may not be allowed as evidence in trials.
Definition of the chain of custody
In practice, a chain of custody is a chronological record on paper that documents when, how, and by whom evidence or individual items of physical or electronic evidence were collected, handled, analyzed, or controlled. Some items considered in almost all criminal investigations are cell phone records. Under the law, an item will not be accepted as evidence at trial, nor will it be seen by a jury, unless the chain of custody has an unbroken and properly documented trail, with no gaps or discrepancies. To convict a defendant of a crime, the evidence against him must have been carefully handled to avoid tampering or contamination.
For criminal investigators López y Gómez, the chain of custody “is a procedure established by legal regulations, which has the purpose of guaranteeing the integrity, conservation and inalterability of material evidence such as documents, samples (organic and inorganic), weapons of fire, projectiles, vanillas, bladed weapons, narcotics and their derivatives, etc., delivered to crime or forensic laboratories by the competent authority in order to analyze and obtain, by experts, technicians or scientists, an expert opinion. ”
In cases where the evidence did not follow the chain of custody, the procedural activity is considered defective and spurious or illegal evidence, consequently, it is essential to guarantee it at all times in order to arrive at the truth of the criminal act.
In court, the prosecution presents chain of custody documentation to show that the piece of evidence is, in fact, related to the alleged crime and had been in the possession of the defendant or defendant. In an effort to establish a reasonable doubt of guilt, the defense looks for loopholes or acts of mishandling in the chain of custody to show, for example, that evidence may have been fraudulently “planted” or “manipulated” so that the accused person or indicated appears guilty.
In the OJ Simpson trial, for example, Simpson’s defense demonstrated that blood samples from the crime scene had been in the possession of various investigating officers for various periods of time, without being properly recorded on the chain of chain form. custody. This omission allowed the defense to create reasonable doubt in the minds of the jury that the blood evidence linking Simpson to the crime could have been planted or contaminated to incriminate him.
It is of the utmost importance that from the time it is collected until it is presented in court, an item of evidence must always be in the physical custody of an identifiable and legally authorized person. Therefore, a chain of custody in a criminal case could be:
- A police officer picks up a gun (preferably wearing gloves or being careful not to contaminate it with his fingerprints) at a crime scene and places it in a sealed container, paper envelope, or zip-seal bag.
- The police officer hands the gun over to a police forensic technician.
- The forensic technician removes the gun from the container or bag, collects the fingerprints and other evidence present on the weapon (ballistics tests), and places the gun along with the collected evidence in the sealed container.
- The forensic technician hands over the weapon and related evidence to a police evidence technician.
- The evidence technician keeps the weapon and all related evidence in a secure location and records everyone who accesses the evidence during the investigation until the end of the case.
Test items are often moved in and out of the place where they are kept or stored and are handled by different people. All changes in the possession, handling, and analysis of items of evidence must be recorded on the chain of custody form .
Chain of Custody Form
The Chain of Custody (FCC) form is used to record all changes in the seizure, custody, control, transfer, analysis, and disposition of physical and electronic evidence. A typical chain of custody form will describe the evidence and detail the location and conditions under which the evidence was collected. As evidence progresses through the investigation, the FCC should be updated to show traceability, at a minimum:
- The identity and signature of each person who handled the evidence and their authority to do so.
- How long the evidence was in the possession of each person who handled it.
- How the evidence was transferred each time it changed hands.
The chain of custody form may only be handled by persons identified as having the authority and competence to possess the evidence, such as police officers and detectives, forensic analysts and experts, certain court or prosecution officials, and evidence technicians (ballistics experts). , dactyloscopy, DNA, graphotechnics).
Chain of custody in civil cases
While it is more common to establish a chain of custody form for cases handled by the criminal justice system, a chain of custody may also be required in civil cases, such as lawsuits arising out of incidents involving persons driving under the effects of alcohol or those acts of medical negligence or paternity tests.
For example, victims of car accidents caused by drunk and uninsured drivers often must sue the offending driver for damages in civil court. In such cases, the injured plaintiff will need to show evidence of the accused driver’s (positive) blood alcohol test after the accident. To prove the validity of that evidence, the plaintiff will need to show that the defendant’s blood samples followed an unbroken chain of custody. The lack of a satisfactory chain of custody could prevent blood test results from being considered as evidence in court.
Similarly, in medical malpractice cases, medical and hospital records handled through an unbroken chain of custody must be produced as evidence.
Other important areas of the chain of custody
In addition to crime scene investigations and civil lawsuits, some cases where chain of custody is important include:
- The tests in athletes for the use of prohibited substances in competitions.
- Tracing food products to ensure they are authentic and ethically sourced.
- In research involving the use of animals to ensure that they were treated under ethical and morally acceptable standards.
- In clinical trials of new drugs and vaccines.
- When establishing provenance: proof of authenticity and chronology of ownership and location of works of art, antiquities and documents, archaeological objects, stamps and rare coins.
- When tracking missing letters, packages or other postal products.
- In the acquisition of medicines that are used for execution with lethal injection.
- In the seizure of valuables by customs departments, income tax or revenue.
- A chain of custody is particularly important in environmental sampling to establish responsibility for contamination and the accidental release of hazardous waste.
Finally, it should be noted that in order to correctly establish the chain of custody, all the elements and procedures involved must be considered, these are: people, standards, methods and techniques, information, containers and places, in order to register and guarantee the authenticity and conservation of the evidence collected during the time that the case remains open.
Additional sources and references
- Bergman, Paul. “Chain of custody for evidence”. At https://www.nolo.com/legal-encyclopedia/what-chain-custody.html
- Lopez Calvo, Pedro and Pedro Gomez Silva. “Criminal and Forensic Investigation”. Colombia, Editorial Temis, SA (2000).
- “ Federal Rules of Evidence: Rule 901. Authentication or Identification of Evidence .” Cornell Law School. At https://www.law.cornell.edu/rules/fre/rule_901
- Kolata, Gina . “ The OJ Simpson case shows the need for proper use of forensic science . ” New York Times (1995).
- “Chain of Custody Forms for Drug Testing.” Mediplex United, Inc.
