BASIS OF EXPERT TESTIMONY IN
COURT OF LAW
By:
SANAH ASHRAF
Advocate High Court,
ABSTRACT
As
a general rule witness may only give evidence of facts of which they have
personal knowledge. In other words a person can give evidence of what he
himself did, said, heard or witnessed. Law of evidence prohibits witnesses from
expressing their opinion about what happened or what may have happened. It is
exclusive domain of courts to draw inferences from the facts and make value
judgment from them. However there are some areas of science or arts that
require special knowledge, skill, training, education or expertise which a
judge cannot be expected to possess for example audio video analysis of CCTV
camera recording that whether it is tempered or not? In such specialized area
experts are allowed to testify. This is done to ensure that court does not draw
erroneous inferences from the evidence before it and that it is properly
equipped to determine how much weight if any to give to evidence to which the
expertise relate and this is basis for admissibility of an expert evidence in
court of law.
WHO IS AN EXPERT?
v Article 59 of
Qanun-e-Shahadat Order, 1984 stated as under:-
“Opinion of experts: when the court
has to form an opinion upon a point of foreign law, or of science, or art, or
as a identity of handwriting or finger impressions, the opinion upon that point
of persons specially skilled in such foreign law, science or art, or in
questions as to identity of handwriting or finger impressions are relevant
facts.
Such persons are called experts”
v Section 2(f) of
the Punjab Forensic Science Agency Act 2007 defines expert as under:-
“Expert includes a qualified foreign
expert working in a forensic science facility and whose evidence is admissible
in the country of his origin.”
v Section 3(f) of
Investigation for Fair Trial Act, 2013 defines experts as under:-
“Expert means a person qualified or
trained or experienced in conducting surveillance or interception who is
nominated by the applicant or the federal Government as an expert for analysis
of the intercepted material.”
Expert
is a person who has specialized knowledge or skill or expertise in any of
following area.
1.
Foreign
Law
2.
Science
or Art e.g. computer forensic, DNA etc
3.
Identity
of Handwriting
4.
Identity
of finger impression.
PRINCIPLES OF LAW
OF EVIDENCE
In
strict sense of law, Evidence means anything which is admissible in court of
law and can be either oral, documentary or real evidence. It must disclose
about some fact that can be physical fact i.e. anything, state if things, or
relation of things capable of being perceived by the senses or psychological
fact i.e. any mental condition of which any person is conscious.
Article
71 of Qanun-e-Shahadat Order 1984 states that evidence must be direct that is
to say:-
If it refers to a
fact that could be seen it must be evidence of a witness who says he saw it.
If it refers to a
fact which could be heard, it must be evidence of a witness who says he heard
it.
If it refers to a
fact which could be perceived by any other sense or in any other manner, it
must be evidence of a witness who says he perceived it by that sense or in that
manner.
Article
59 of Qanun-e-Shahadat Order 1984 creates exception and opinions of persons
specially skilled in foreign law, science, or art, or in questions as to the
identity of handwriting or finger impressions are relevant facts.Experts
although are not witness to crime, yet on the basis of their expertise they can
draw inference from evidence recovered from crime scene, or during
investigation provided if such evidence
comes within scope of their expertise.
PAKISTAN
LAW REGARDING ADMISSIBILITY OF EXPERT EVIDENCE:-
Ø
PROVISIONS OF QANUN E SHAHADAT ORDER 1984
Relevant Articles
59. Opinions of
experts:
When the Court
has to form an opinion upon a point of foreign law, or of science or art, or as
to identity Of handwriting or finger impressions; the opinions upon that point
of persons specially skilled in such foreign law, science or art, or in
questions as to identity of hand-writing or finger impressions are relevant
facts. Such persons are called experts. Illustrations(a) The question
is, whether the death of A was caused by poison. The opinion of experts as to
the symptoms produced by the poison by which A is supposed to have died, are
relevant.
(b) The question
is, whether A, at the time of doing a certain act, was by reason of unsoundness
of mind, incapable of knowing the nature of the act, or that he was doing what
was either wrong or contrary to law. The opinions of experts upon the question
whether the symptoms exhibited by A commonly show unsoundness of mind, and
whether such unsoundness of mind usually renders persons incapable of knowing
the nature of the acts which they do, or of knowing that what they do either
wrong or contrary to law are relevant.
(c) The question
is whether a certain document was written by A, Another document is produced
which is proved or admitted to have been written by A. The opinions of experts
on the question whether the two documents were written by the same person or by
different persons are relevant.
60. Facts bearing
upon opinions of experts:
Facts not
otherwise relevant, are relevant if they support or are inconsistent with the
opinions of experts, when such opinions are relevant.
Illustrations. (a) The question
is, whether A was poisoned by a certain poison. The fact that other persons,
who were poisoned by that poison, exhibited certain symptoms which experts affirm
or deny to be the symptoms of that poison, are relevant.
(b) The question
is, whether an obstruction to a harbour is caused by a certain sea wall.
The fact that
other harbours similarly situated in other respects, but where there were no
such sea-walls, began to be obstructed at about the same time, is relevant.
61. Opinion as to
hand-writing when relevant:
When the Court
has to form an opinion as to the person by whom any document was written or
signed, the opinion of any person acquainted with the hand-writing of the
person by whom it is supposed to be written or signed that it was or it was not
written or signed by that person, is relevant fact.
Explanation: A person is said
to be acquainted with the hand-writing of another person when he has seen that
person write, or when he has received documents purporting to be written by
that person in answer to documents written by himself or under his authority
and addressed to that person, or when, in the ordinary course of business,
documents purporting to be written by that person have been habitually
submitted to him.
Illustrations
The question is
whether a given letter is in the handwriting of A, a merchant in London.
B is a merchant
in Peshawar, who has written letters addressed to A and received letters
purporting to be written by him, C is B's clerk, whose duty it was to examine
and file B’s correspondence. D is B's broker, to whom B habitually submitted
the letters purporting to be written by A for the purpose of advising him
thereon.
The opinion of B,
C and D on the question whether the letter is in the handwriting of A are
relevant though neither B, C or D ever saw A write.
65. Grounds of
opinion when relevant:
Whenever the
opinion of any living person is relevant, the grounds on which such opinion is
based are also relevant.
Ø
PROVISIONS OF THE PUNJAB FORENSIC SCIENCE AGENCY ACT
2007
Relevant
Sections:-
9. Experts. (1)The Government shall appoint an
expert in the prescribed manner.
(2) No person shall be appointed as an expert
unless he is qualified to conduct examination of a forensic material.
(3) A person appointed in the Agency as an
expert shall be deemed as an expert appointed under section 510 of the Code and
a person specially skilled in a forensic material under Article 59 of the
Qanun-e-Shahadat Order, 1984 (X of 1984).
(4) The Government or the Agency shall not
entrust examination of a forensic material to a person who has been convicted
of an offence related to giving false evidence under any law for the time being
in force.
10. Expert
opinion.
(1) A Court, tribunal or authority
may send to the Agency, a forensic material related to investigation or
proceedings before it, for examination and expert opinion.
(2) The Agency shall authenticate and send
expert opinion to a Court, tribunal or authority in the prescribed manner.
(3) An expert opinion shall carry the name
and designation of the expert who conductedthe examination.
11. Clarification
in case of certain opinion.—
(1) If an expert opinion is not clear, the
Court,tribunal or authority may refer it to the Agency for clarification on a
spelcific question.(2) The
Agency shall, on receipt of the reference, send clarification on the question
to the Court, tribunal or authority.
(3) If the condition of the forensic material
or any other fact does not allow submission of a clear answer to the question,
the Agency shall state its inability to answer the question.
12. Re-examination of forensic material.—
(1) A person affected by the opinion of an
expert, may for a sufficient cause, submit an application for re-examination
before the Court, tribunal or authority other than a police officer before
which the opinion is rendered or the Court or tribunal before which the opinion
is submitted by the authority.
(2) If the Court,
tribunal or authority is satisfied that there are sufficient grounds for
re-consideration of the opinion, it may, for reasons to be recorded in writing,
direct the Agency to re-examine the forensic material.
(3) The Director
General shall, on receipt of the direction, constitute a panel of three or more
experts to re-examine the forensic material or refer the same to a forensic
examination facility for examination and opinion.
(4) The Director
General shall submit the finding of the expert or the forensic facility and his
opinion to the Court, tribunal or authority.
Ø
PROVISIONS OF CODE OF CRIMINAL PROCEDURE 1898:-
Section 510. Report of Chemical Examiner, Serologist
etc.
Any document
purporting to be a report, under the hand of any Chemical Examiner or Assistant
Chemical Examiner to Government [or of the Chief Chemist of Pakistan Security
Printing Corporation, Limited] or any Serologist, finger print expert or
fire-arm expert appointed by Government upon any matter or thing duly submitted
to him for examination or analysis and report in the course of any proceeding
under this Code, may without calling him as a witness, be used as evidence in
any inquiry, trial or other proceeding under this Code: Provided that the Court
may [if it considers necessary in the interest of justice] summon and examine
the person by whom such report has been made.]
BASIS OF EXPERT
TESTIMONY IN COURT OF LAW
Whether
evidence of an expert is admissible or not
and basis of testimony of expert witness in court of law can be
discussed as following:-
MATTERS WHICH THE COURT CONSIDERS
CALL FOR THE SPECIAL SKILL OR KNOWLEDGE OF AN EXPERT: THE HELPFULNESS TEST
An
expert opinion is admissible only if it can furnish the court with scientific
information which is likely to be outside the knowledge and experience of a
judge. If on proven facts judge can form his own conclusion without help of an
expert, then opinion of an expert is unnecessary.
For
example in issues of Mens Rea, the court will not admit expert evidence because
Judge does not need expert help in deciding on intentions of a man with a
normal mind unless it is alleged that offender was insane at the time of
commission of offence.
However
there are certain areas of forensic science where only expert witness can
testify e.g. Forensic Toxicology, Ballistic Experts, finger prints Experts etc.
In these specialized fields evidence of experts is extremely useful to courts.
RELEVANCY:-
Articles 18 of Qanun-e-Shahadat
Order 1984 restricts scope of evidence that is admissible in any suit or
proceedings. It embodies principle that evidence may be given in any suit or
proceeding of the existence or non-existence of every fact in issue and of such
other facts as are declared to be relevant under Qanun-e-Shahadat Order 1984
and of no others.
Expert testimony can only be given
regarding those facts that are subject matter of litigation and are either fact
in issue or relevant facts. Any fact which is not disputed is admission and
need not to be proved and in such case there is no need of expert evidence e.g.
If subject matter of litigation is whether A committed rape with B or not? And
evidence of fingerprint expert is given who testifies that he found match of
fingerprints of A with fingerprints found at crime scene. Here it is irrelevant
because A may be present there as witness, or he may be present but has not
committed rape and presence is not fact in issue, fact in issue is rape which
can be proved by testimony of DNA expert . Here evidence of DNA is more
relevant that can establish presence or absence of DNA/semen of A on the
victim's body,DNA of A is to be matched
from DNA profile of swab taken from B at the time of her medical examination
which can establish whether A committed rape or not? Evidence of fingerprint in
present situation can be probative but is irrelevant.
RELIABILITY OF EXPERT EVIDENCE
Expert evidence must be reliable
“General Acceptance” test set out in Frye v United States states as under:-
“the thing from which the deduction
is made must be sufficiently established to have gained general acceptance in
the particular field to which it belongs”
However Frye standard was over-ruled
by Daubert standard.
Where expert dose not set out
scientific criteria for testing the validity of his opinion, the bare opinion
will have little force. Since it cannot be tested by cross-examination.
Ø Indication of Reliability include:-
·
Peer
Review
·
Publication
·
The
known or potential rate of errors
·
Existence
and maintenance of standards controlling the operation of the particular
scientific techniques.
ROLE OF AN EXPERT
Evidence
given by an expert should be independent, uninfluenced as to form and content.
He must provide independent assistance to court. It must be objective, unbiased
opinion in relation to matters within his expertise. Role of expert is not to assume
the jurisdiction of court. An expert role is to testify the facts upon which
his opinion is based so that it may help the court in understanding trier of
fact.
AMERCIAN CASE LAW
THE FRYE STANDARD:-
Scientific
Evidence and the Principle of General Acceptance
In
1923, in Frye v.
Just
when a scientific principle or discovery crosses the line between the
experimental and demonstrable stages is difficult to define. Somewhere in this
twilight zone the evidential force of the principle must be recognized, and
while the courts will go a long way in admitting experimental testimony deduced
from a well-recognized scientific principle or discovery, the thing from which
the deduction is made must be sufficiently established to have gained general
acceptance in the particular field in which it belongs.
Essentially,
to apply the “Frye Standard” a court had to decide if the procedure, technique
or principles in question were generally accepted by a meaningful proportion of
the relevant scientific community. This standard prevailed in the federal
courts and some states for many years.
THE DAUBERT STANDARDS:-
Court Acceptance
of Expert Testimony
In
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) and later cases
the Court explained that the federal standard includes general acceptance, but
also looks at the science and its application. Trial judges are the final
arbiter or “gatekeeper” on admissibility of evidence and acceptance of a
witness as an expert within their own courtrooms.
In
deciding if the science and the expert in question should be permitted, the
judge should consider:
1.
What
is the basic theory and has it been tested?
2.
Are
there standards controlling the technique?
3.
Has
the theory or technique been subjected to peer review and publication?
4.
What
is the known or potential error rate?
5.
Is
there general acceptance of the theory?
6.
Has
the expert adequately accounted for alternative explanations?
7.
Has
the expert unjustifiably extrapolated from an accepted premise to an unfounded
conclusion?
The
Daubert Court also observed that concerns over shaky evidence could be handled
through vigorous cross-examination, presentation of contrary evidence and
careful instruction on the burden of proof.
In
many US states, scientific expert testimony is now subject to this Daubert
standard. But some states still use a modification of the Frye standard.
PRINCIPLE OF
ENGLISH LAW
WHO IS EXPERT?
IN
Robb (1991) 93 Cr.App.R.61.CF Bingham L.J set out valuable statement of
principle:-
“The old-establishment,
academically-based science such as medicine, geology, or metallurgy, and the
established professions such as architecture, quantity surveying or
engineering, present no problem. The field will be regarded as one in which
expertise may exist and only properly qualified. Member will be accepted
without questions expertise. Expert evidence is not, however limited to these
core areas-----Some of these fields are far removed from anything which could
be called a formal scientific discipline. Yet while receiving this evidence the
courts would not accept the evidence of an astrologer, a soothsaye a
witch-doctor or an amateur psychologies ----The last test which the English
common law has developed is characteristically pragmatic [Bingham L.J then
cited a passage from the judgment of Lord Russell of Killowen C.J in Silverlock
and continued…..]
Thus the essential questions are
whether study and experience will give a witnesses opinion an authority which
the opinion of one not so qualified will lack, and (if so) whether the witness
in question is [skilled and has on adequate knowledge]……
If these conditions are met the
evidence of the witness is in law admissible although the weight to be attached
to his opinion must of course be assessed by the tribunal of fact.”
CONCLUSION
In
deciding if the science and the expert in question should be permitted, the
judge should consider:
Ø Is there any need
for Expert testimony to understand trier of fact?
Ø Does the expert
possess necessary qualification, skill or training?
Ø Is expert
experssing his opinion in unbiased way or is he prejudiced?
Ø What is the basic
theory and has it been tested?
Ø Are there
standards controlling the techniques?
Ø Has the theory or
technique been subjected to peer review and publications?
Ø What is a known
or potential error rate?
Ø Is there general
acceptance of theory?
Ø Has the expert
adequately accounted for alternative explanations?
Ø Has the expert
unjustifiably extrapolated from an accepted premise to unfolded conclusions?
Expert
testimony is helpful to court in understaning trier of fact and draw inferences
on matters that require special skill. However experts role is not to assume
jurisdiction of court and determine guilt or innocence.Duty of expert to court
is to state opinion and grounds of his opinion and it is privilige of court to
determine what evidentiary value should be given to such opinions.
REFERENCES
1. Qanun-e-Shahadat
Order 1984
2. The
Punjab Forensic Agency Act 2007
3. Investigation
for Fair Trail Act 2013
4. Code
of Criminal Procedure 1898
5. Law
of Evidence by I.H.DENNIS (Sweet & Maxwell)
6. Qanun-e-Shahadat
Order, 1984 by Justice Khalil-ur–Rehman