NOTES ON CRIME DETECTION AND INVESTIGATION
CDI-1: FUNDAMENTALS OF CRIMINAL INVESTIGATION
CRIMINAL INVESTIGATION – is an art which deals with the identity and location of the offender and
provides evidence of guilt through criminal proceedings.
INVESTIGATION DEFINED: The collection of facts to accomplish a three-fold aim:
a. to identify the guilty party;
b. to locate the guilty party; and
c. to provide evidence of his guilt.
PRIMARY JOB OF AN INVESTIGATOR
The primary job of the investigator is to discover whether or not an offense has been committed
under the law, after determining what specific offense has been committed, he must discover how it was
committed, by whom, where it was committed, when and why it was committed (Cardinal points of
Investigation 5W’s and 1H).
SIX CARDINAL POINTS OF INVESTIGATION
WHAT specific offense has been committed? Nature of crime
WHERE crime was committed? Place or location
WHEN it was committed? Time and date
WHOM it was committed? Persons/s involved
WHY it was committed? Reason or motive of
Committing the crime
HOW it was committed? Manner, method or modus
operandi
QUALITIES OF A GOOD INVESTIGATOR
1. Perseverance
2. Intelligence
3. Honest
4. Understanding of the people and environment
5. Keen power of observation
TRAINING
Training, as one of the foundations of investigation, is concededly a vital ingredient in the creation
of a total investigator. Experience alone does not make one good investigator. Many who had been
hostage to this notion often ended in jeopardy. The ideal conjugal partnership is training and experience.
The fusion of the best training and vast experience is a formidable force that can threat even the most
sophisticated technology and syndicated crimes. The necessity of training as a purveyor of change builds
the investigator’s confidence. It widens his vision for professional growth and strengthens his will to
survive and prevail over crises.
The National Forensic Science Training Institute (NFSTI) under the Philippine Public Safety
College is the institution that trains uniformed personnel of the Philippine National Police to become a
certified investigator.
THREE TOOLS OF INVESTIGATION
1. INFORMATION
It is the knowledge/data which an investigator acquired from other persons and records.
Classes of Information
a. Regular Sources – records, files from government and non-government agencies, news items.
b. Cultivated Sources – information gathered upon initiative of the investigator from informants,
vendors, taxicab driver, GRO, and others.
c. Grapevine Sources – these are information coming from the underworld characters such as
prisoners and ex-convicts.
2. INTERVIEW AND INTERROGATION
INTERVIEW – Is a conversation with a purpose, motivated by a desire to obtain certain
information from the person being interviewed as to what was done, seen, felt, heard, tasted, smell or
, I.R.O.N.I.C. FORMAT
The interview of a witness can be described by its acronym ‘IRONIC’ which stands for Identity,
Rapport, Opening Statement, Narration, Inquiry, and conclusion.
Identity – prior to the commencement of an interview, the investigator should identify himself to
the subject by name, rank and agency. Except, when there is no need to know the officer’s identity.
Rapport – it is good to get the positive feeling of the subject towards the investigators, such
friendly atmosphere is a vital for both the subject and the investigator t have a better interaction.
Opening Statement – the investigator must have to indicate why the subject is being contracted.
Narration – the witness should be allowed to tell all he knows with little interruptions from the
investigator.
Inquiry – after all information have been given by the subject, that is the time for the investigator
to as question to clarify him about the case under investigation.
Conclusions – after the interview, it is but proper to close the interview with outmost courtesy
and thanking the subject for his cooperation.
RULES TO BE OBSERVED IN QUESTIONING
a. One question at a time
b. Avoiding implied answer
c. Simplicity of the questions
d. Saving faces
e. Avoid close ended questions (yes or no)
INTERROGATION –is a questioning of a person suspected of having committed an offense or a
person who is reluctant to make full disclosure of information in his possession which is pertinent to the
investigation.
What are the purposes of Interrogation?
a. To obtain confession to the crime
b. To induce the suspect to make admission
c. To learn the facts of the crime
d. To learn the identity of the accomplice
e. To develop information which will lead to the recovery of the fruits of the crime
f. To discover the details of other crimes participated by the suspect
INTERROGATION TECHNIQUES
Emotional Appeal
Place the subject in the proper frame of mind. The investigator should provide emotional stimuli
that will prompt the subject to unburden himself by confiding. Analyze the subject’s personality and decide
what motivation would prompt him to tell the truth, and then provide those motives through appropriate
emotional appeals.
Sympathetic appeal
The suspect may feel the need for sympathy or friendship when he is apparently in trouble.
Gestures of friendship may win his cooperation.
Kindness
The simplest technique is to assume that the suspect will confess if he is treated in a kind and
friendly manner.
Extenuation
The investigator indicates he does not consider his subject’s indiscretion a grave offense.
Shifting the blame
The interrogator makes clear his belief that the subject is obviously not the sort of person who
usually gets mixed up in a crime like this. The interrogator could tell from the start that he was not dealing
with a fellow who is a criminal by nature and choice.
Mutt and Jeff
Two (2) Agents are employed.
- Mutt, the relentless investigator, who is not going to waste any time because he
knows that the subject is guilty.
- Jeff, on the other hand, is obviously a kind-hearted man.
Bluff on a Split Pair
This is applicable when there is more than one suspect. The suspects are separated and one is
informed that other has talked.
Pretense of Physical Evidence
CDI-1: FUNDAMENTALS OF CRIMINAL INVESTIGATION
CRIMINAL INVESTIGATION – is an art which deals with the identity and location of the offender and
provides evidence of guilt through criminal proceedings.
INVESTIGATION DEFINED: The collection of facts to accomplish a three-fold aim:
a. to identify the guilty party;
b. to locate the guilty party; and
c. to provide evidence of his guilt.
PRIMARY JOB OF AN INVESTIGATOR
The primary job of the investigator is to discover whether or not an offense has been committed
under the law, after determining what specific offense has been committed, he must discover how it was
committed, by whom, where it was committed, when and why it was committed (Cardinal points of
Investigation 5W’s and 1H).
SIX CARDINAL POINTS OF INVESTIGATION
WHAT specific offense has been committed? Nature of crime
WHERE crime was committed? Place or location
WHEN it was committed? Time and date
WHOM it was committed? Persons/s involved
WHY it was committed? Reason or motive of
Committing the crime
HOW it was committed? Manner, method or modus
operandi
QUALITIES OF A GOOD INVESTIGATOR
1. Perseverance
2. Intelligence
3. Honest
4. Understanding of the people and environment
5. Keen power of observation
TRAINING
Training, as one of the foundations of investigation, is concededly a vital ingredient in the creation
of a total investigator. Experience alone does not make one good investigator. Many who had been
hostage to this notion often ended in jeopardy. The ideal conjugal partnership is training and experience.
The fusion of the best training and vast experience is a formidable force that can threat even the most
sophisticated technology and syndicated crimes. The necessity of training as a purveyor of change builds
the investigator’s confidence. It widens his vision for professional growth and strengthens his will to
survive and prevail over crises.
The National Forensic Science Training Institute (NFSTI) under the Philippine Public Safety
College is the institution that trains uniformed personnel of the Philippine National Police to become a
certified investigator.
THREE TOOLS OF INVESTIGATION
1. INFORMATION
It is the knowledge/data which an investigator acquired from other persons and records.
Classes of Information
a. Regular Sources – records, files from government and non-government agencies, news items.
b. Cultivated Sources – information gathered upon initiative of the investigator from informants,
vendors, taxicab driver, GRO, and others.
c. Grapevine Sources – these are information coming from the underworld characters such as
prisoners and ex-convicts.
2. INTERVIEW AND INTERROGATION
INTERVIEW – Is a conversation with a purpose, motivated by a desire to obtain certain
information from the person being interviewed as to what was done, seen, felt, heard, tasted, smell or
, I.R.O.N.I.C. FORMAT
The interview of a witness can be described by its acronym ‘IRONIC’ which stands for Identity,
Rapport, Opening Statement, Narration, Inquiry, and conclusion.
Identity – prior to the commencement of an interview, the investigator should identify himself to
the subject by name, rank and agency. Except, when there is no need to know the officer’s identity.
Rapport – it is good to get the positive feeling of the subject towards the investigators, such
friendly atmosphere is a vital for both the subject and the investigator t have a better interaction.
Opening Statement – the investigator must have to indicate why the subject is being contracted.
Narration – the witness should be allowed to tell all he knows with little interruptions from the
investigator.
Inquiry – after all information have been given by the subject, that is the time for the investigator
to as question to clarify him about the case under investigation.
Conclusions – after the interview, it is but proper to close the interview with outmost courtesy
and thanking the subject for his cooperation.
RULES TO BE OBSERVED IN QUESTIONING
a. One question at a time
b. Avoiding implied answer
c. Simplicity of the questions
d. Saving faces
e. Avoid close ended questions (yes or no)
INTERROGATION –is a questioning of a person suspected of having committed an offense or a
person who is reluctant to make full disclosure of information in his possession which is pertinent to the
investigation.
What are the purposes of Interrogation?
a. To obtain confession to the crime
b. To induce the suspect to make admission
c. To learn the facts of the crime
d. To learn the identity of the accomplice
e. To develop information which will lead to the recovery of the fruits of the crime
f. To discover the details of other crimes participated by the suspect
INTERROGATION TECHNIQUES
Emotional Appeal
Place the subject in the proper frame of mind. The investigator should provide emotional stimuli
that will prompt the subject to unburden himself by confiding. Analyze the subject’s personality and decide
what motivation would prompt him to tell the truth, and then provide those motives through appropriate
emotional appeals.
Sympathetic appeal
The suspect may feel the need for sympathy or friendship when he is apparently in trouble.
Gestures of friendship may win his cooperation.
Kindness
The simplest technique is to assume that the suspect will confess if he is treated in a kind and
friendly manner.
Extenuation
The investigator indicates he does not consider his subject’s indiscretion a grave offense.
Shifting the blame
The interrogator makes clear his belief that the subject is obviously not the sort of person who
usually gets mixed up in a crime like this. The interrogator could tell from the start that he was not dealing
with a fellow who is a criminal by nature and choice.
Mutt and Jeff
Two (2) Agents are employed.
- Mutt, the relentless investigator, who is not going to waste any time because he
knows that the subject is guilty.
- Jeff, on the other hand, is obviously a kind-hearted man.
Bluff on a Split Pair
This is applicable when there is more than one suspect. The suspects are separated and one is
informed that other has talked.
Pretense of Physical Evidence
