Preliminary Investigation

Preliminary Investigation
Securing a Crime Scene

This is the first aspect of a preliminary investigation. A crime scene is a spot, area or surrounding where an act which has resulted into a crime has taken place. According to Locard’s Exchange Principle, every contact leaves a trace. Crime Scene Investigation (CSI) is therefore very important as it leads the investigator to the perpetrator. Types of crime scenes and their characteristics include:

  1. Indoor crime scenes:
    • Easy to demarcate
    • Easy to secure
    • Has less exposure to contamination
  2. Outdoor crime scenes:
    • Difficult to demarcate
    • Difficult to secure
    • Vulnerable to contamination
    • Vulnerable to changes in weather conditions
  3. Conveyance crime scenes:
    • Easy to demarcate
    • Easy to secure
    • Has less exposure to contamination
    • But is difficult to search
  4. Digital crime scenes:
    • Difficult to demarcate as evidence can transcend borders over the internet
    • Difficult to secure
    • Has less exposure to contamination
    • Needs specialized training and expertise to analyze and search.
Points to Keep in Mind When Carrying Out a CSI
  1. Observe all requisite safety procedures.
  2. Attend to any injured persons or animals at the scenes and ensure that they get emergency care.
  3. Secure the scene.
  4. Control any persons at the scene.
  5. Establish and preserve the scene boundaries.
  6. Document actions and observations at the scene.
  7. Conduct a scene assessment.
  8. Conduct a scene “walk-through”.
  9. Search the scene using the chosen search pattern.
  10. Flag any potential evidence with numbered tags.
  11. Photograph the scene with the flagged exhibits.
  12. Take measurements of the scene and prepare a rough sketch.
  13. Prioritize collection of evidence.
  14. Collect, preserve, inventorise and package evidence.
  15. Complete and record the CSI.
  16. Debrief the team and perform a final survey of the crime scene.
Search and Seizure

Preliminary InvestigationAfter securing a crime scene, the next step in a preliminary investigation is search and seizure. A search is an operation whereby an investigator looks for and take possession of alleged evidence. In general, an officer should obtain a search warrant before conducting a search. However, this is not required where circumstances allow an officer to conduct the search without a warrant. This is because the law recognizes the need to protect property owners from arbitrary interference of their property by persons in authority with intention to annoy. Therefore, the law requires that a person who for the purpose of any inquiry wishes to search for any item in another’s premises should only do so with authority. The authority may be in form of a search warrant that the court has issued.

During the preliminary investigation, if the investigator has reasonable grounds to believe that he can find the evidence in a particular place, he may go ahead and search without a warrant. Therefore, the investigator may conduct a search without a warrant if seeking the warrant will occasion delay and jeopardize expected results. Note that in case of complaint by a suspect that the search was illegal, the investigator should be able to defend his/her reasonableness in his/her act.


Preliminary InvestigationThe law prohibits arbitrary arrests and unlawful detention. Human rights provide for the right to liberty. No person shall be deprived of their liberty. However, this rule has exceptions.  An example is where the law allows an officer to deprive liberty on legal grounds and in accordance to legal procedures. Further, an officer may not subject any person to arbitrary arrest. The law also disallows officers to detain people without charges or convictions.

Rights of Arrested Persons

Another aspect of a preliminary investigation is arresting suspects. Officers must respect the rights of persons they arrest. These rights are:

  • Officers must inform arrested persons promptly and in a language they understand, why they are under arrest and of any charge against them.
  • Officers must inform arrested persons promptly, in a language that they understand, that any statement the arrested person makes may become evidence against them in court.
  • Arrested persons have the right to remain silent.
  • Officers must bring arrested persons before a court within reasonable time that the law has defined. This shall not include the time reasonably required for the journey from the place of arrest to the court.
  • Officers must give arrested persons prompt and specific explanations of the reasons for their arrest due to the alleged crime committed.
  • Arrested persons have the right to petition the court to order their physical release where the arresting police officer or the law enforcer fails to bring them before a court within the prescribed time and to provide reasons for their arrest.
  • Officers should not compel arrested persons to make confessions or admissions. Any evidence obtained under coercion shall not be admissible.
  • The court may release arrested persons on bail. In exceptional circumstances prescribed by law, the court may deny bail or demand adequate guarantee for the conditional release of the arrested person.

Most African countries give police and other government officers powers of arrest. Such officers, under special provisions of the law, may arrest a suspect without a warrant in the case of flagrant offences. Wildlife laws give wildlife wardens, rangers and scouts powers to arrest offenders committing flagrant wildlife offences.

Lawful Procedure for Carrying Out an Arrest
  1. The officer making an arrest shall first establish the identity of the person to be arrested.
  2. Where the arrest is made with a warrant, the officer shall read out the contents of the warrant to the person to be arrested and shall show it to the person arrested if he so requests.
  3. The officer shall then actually touch or confine the body of the person to be arrested unless there is a submission to his custody by word or action.
  4. If such person forcibly resists the endeavors to arrest or attempts to evade the arrest, such officer may use all means proportionate to the circumstances to effect the arrest.
  5. Where the police call for assistance in making an arrest with or without warrant, all citizens shall have a duty to assist where assistance can be given without risk.
  6. Where an arrest is made, the person making the arrest shall without unnecessary delay hand over the person so arrested to the nearest police station.

Author: DidiWamukoya

2 thoughts on “Preliminary Investigation

  1. I found this article very informative about “Investigations”. Looking forward for more informative articles like this.

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