Evidence plays a major role in every judicial proceeding whether it is criminal or civil case. The use of expert opinion was first allowed by Lord Mansfield. Lord Mansfield allowed an expert's opinion in the facts of other witnesses in the case of Folkes Vs. Chadd in the year 1782.

In the late 20th century the common legal system stated some duties as to how expert opinions are to be used as evidences. Opinion of an expert plays vital role in evidence. This article focuses on the expert's opinion and how the opinions stated by an expert are relevant. Generally, a witness is served with summons to describe the mere facts of the case, the expert is also considered as witness even if he does not know the facts of the case.

The opinion of an expert can reveal some truths about the dead such as the time and cause of death. The duty of an expert is to provide impartial, independent, and unbiased opinion to the court.

Who Is An Expert:

An expert is a person who has been trained or is skilled or has knowledge, experience, or education in technical or scientific and capable of drawing opinions and conclusions from the facts observed by him or noticed by the others.

For example: If the murder weapon is unknown, the court may call a forensic expert to clarify what the weapon was by observing the sustained injury is relevant. Also, a ballistic expert's opinion on a particular gun used as a murder weapon concerning the unique markings is relevant.

In the case, State of Himachal Pradesh Vs. Jai Lal and others it was held that an expert has to be cross examined in the court along with providing opinion as assigned also some functions of experts were stated.

Prerequisites of an expert evidence:
In the case of Ramesh Chandra Agrawal Vs. Regency Hospital Ltd. & Ors. The court laid some requirements of the opinion of an expert also the court stated that the opinion of expert is out of knowledge of any layman.

The requirements are as follows:

1. Expert must be within recognized field of expertise,
2. An opinion must follow reliable principles,
3. Expert must be qualified in discipline.

Duties

1. An expert is supposed to advice the judge to come to conclusion independently
2. His evidence must be advisory,
3. The expert evidence is not the fact of the case.

Types of expert witness:

1. Medical:
   There are many medical experts who are called by the court to provide their opinion on criminal cases such as rape and murder cases. Medical expert opinion contains the opinion of doctors, nurses, laboratory assistants
    
2. Accounting and securities:
   These experts are necessary when there is fraud, misappropriation, breach of obligations in customer-seller relationships also when any bank engages with fraud.
    
3. Forensic:
   Forensic expert play a major role than any other expert in criminal cases.
   A forensic expert may be a biologist or a psychologist. Most of the law agencies employ a forensic expert so that he/she can be an expert witness whenever court requires.
    
4. Vocational:
   Vocational expert does not need to have special knowledge or skill. They just have to provide information on the fact that a particular employee who is stated as disabled can work or not.
    
5. Mental health
   Mental health experts are called to provide opinion on the mental fitness of a person.

 
Opinion of expert:
A belief or judgment given by an expert in a subject is an expert opinion.

Section 45 states that when the court has to form an opinion about:

1. Foreign law,
2. Of science or art,
3. Identity of handwriting,
4. Identity of Finger impressions

The opinions upon that point of specially skilled persons on a particular field are relevant facts. Expert witnesses include doctors, Psychiatrists, ballistic experts, and other professionals instructed by the court to provide an opinion about a fact in legal proceedings.

In the case of Gade Lakshmi Mangaraju v/s. State Of Andhra Pradesh, the court held that the absence of finger impressions does not indicate an absence of a particular person at the scene. In the case where the court has to form an opinion about the science, opinion of such skilled persons in science is a relevant fact, as seen in the case of Sulochana Vs. A.P.S.R.T.C.

• Opinion for foreign law:
  The opinion of an expert in foreign is defined in section 38 read with 45 of the act. It states that the law contained in a book of specific country is relevant. For this, an expert needs to be well versed with the law books of a particular country in order to provide his opinion in foreign law.
   
• Opinion of ballistic expert:
  A firearms expert can give opinion in the case where a gun is involved as a murder weapon.

He can determine the distance by looking at the wound and the type of gun with the bullet can be determined.

Sec. 293 of the criminal procedure code, 1973 deals with the reports of specific Government scientific experts in the court of law. This section states that when the court thinks fit may order to submit reports required for the analysis and can send summons to specific experts to take part in proceedings to clear the doubts on a particular case.

Clause 4 of section 293 names some experts to whom this section applies they are:

1. Any chemical or assistant chemical examiner to government
2. Chief inspector of explosives,
3. Director of a fingerprint bureau,
4. Director of Haffkeine institute, Bombay;
5. Serologist to government,
6. Director or Deputy Director or Assistant Director of a Central Forensic Science Laboratory or a State Forensic Science Laboratory,
7. Any other government expert notified by the central government for this purpose.

Opinion of electronic evidence:
Section 45 A allows opinion of an examiner of electronic evidence in the case where the court is willing to form an opinion on any matter relating to communication or information stored in a computer, or digital form, the opinion of examiner is a relevant fact.

For instance, a person named Rahul is an accused in a criminal conspiracy case, for necessary evidence his mobile phone contains communications made by him can be examined by an expert.

Relevancy Of Expert Opinion:
Section 46 states that the facts, not otherwise relevant, are relevant if they support or are inconsistent with the opinions of the expert, when such opinions are relevant it means that the facts which are not relevant will be relevant if the opinion of expert is supported by them.

Illustration:
A person named Ram, who is a serial killer, has poisoned so many, here the fact that Ankit was poisoned by Ram by observing the symptoms exhibited by all the victims according to the acceptance or denial of the expert is relevant.

Opinion of handwriting expert:
When the court needs an opinion as to the person, by whom a document is written or signed, any other person acquainted with the handwriting whether it is supposed to be done or not by the accused or questioned person is a relevant fact. Section 47 deals with this.

The section states that every person acquainted with the handwriting of a particular person is relevant. It means that the person who is witness to signature or written document.

In the case of shankarappa v. Sushilabai it was held that the wife can be considered as the person acquainted with the handwriting of her husband.

Methods of proving signature/ handwriting in court of law:

1. By calling the person who has signed or written the document,
2. By calling the person who witnessed this,
3. By the opinion of handwriting expert,
4. By comparing the disputed signature or written document with the admitted one,
5. By circumstantial evidence,
6. By the evidence of the person acquainted with the handwriting of the accused.

In the case of Prahlad Saran Gupta v Bar Council of India it was held that the opinion by a handwriting expert is the final and there is no need to confirm it, as a result it stated the importance of expert opinion.

Opinion as to electronic signature:
Section 47 A states that when a court needs to form any opinion as to digital signature, the opinion of the certifying authority issuing certificate is relevant.

Opinion as to existence of a right or custom:
When the court needs to form any opinion as to the existence any of the general right or custom, the opinion of the person who would be likely to know the right or custom if existed or not, is relevant.

For example:
The fact that the certain class of people of the village can drink water from particular well can be proved by the opinion of the elders of the village.

In the case of Radha Krishna Kandolkar v/s. Tukaram, a person was allowed to draw water from a pond for about 30 years. The court held that drawing water since long ago does not make any kind of custom, a custom has to be declared by certain class of people or their elders.

Illustration: The right of particular class of persons of a village to use the water of a particular well is general right.

Opinion as to usages and tenets:
According to section 49 of the act when the court needs to form any opinion on:

1. The tenets of any group of men or a family
2. The wages of any group of men or a family,
3. The constitution and government of any religious or charitable foundation,
4. The meaning of words used in particular districts or any particular class of people,
5. The opinions of person having special knowledge are relevant.

Opinion on relationship:
Section 50 of the act states that when the court needs to form any opinion on any of the relationship from one person to other the opinion which is expressed by the conduct as to the existence of relationship by any of the family member, or any of the person who has special means of knowledge on the subject is relevant.

Exceptions where opinion of relationship is not sufficient

1. To prove marriage in proceedings under divorce act, 1869;
2. Prosecutions under sections of Indian penal code,1860:
   
   1. Section 494: whoever having husband or wife remarry even when they are alive is punishable with imprisonment of term described may extend to 7 years, also shall be liable to fine.
   2. Section 495: the person if conceals the former marriage to the subsequent one is punishable with imprisonment of term described may extend to 10 years, also shall be liable to fine.
   3. Section 497: whoever has sexual inter course with whom he knows or believes to be wife of another man without the consent of that man is punishable with imprisonment of term described may extend to 5 years, also shall be liable to fine.
      However, it was decriminalized by the Supreme Court in the case of Joseph Shine v. Union of India in September 2018.
   4. Section 498: whoever being the husband or a relative of the woman subjects such woman to cruelty is punishable with imprisonment of term described may extend to 3 years, also shall be liable to fine.

In the case of Sree Ram Didwani Vs. Gauri Shankar it was held that for an opinion in existence of relationship, the opinion of a family member or any person specialized in this subject is relevant.

In the case of Bant Singh Vs. Niranjan Singh, there was a dispute in matter of suit of the property where the plaintiff stated defendant as his sister. The opinion of his brother in law who was 80 years old and had good knowledge of his family member was held as the relevant evidence.

Grounds of opinion:
Section 51 of the act states that opinion of any living person and the grounds on which the opinion is based are relevant.

Example: experiments done by an expert to form an opinion.

Conclusion:
An expert opinion is essential in criminal case so as to determine the cause of death which can be done by forensic experts. An expert opinion is not conclusive but it paves a way to serve justice in an efficient manner.

Nowadays, due to pandemic covid-19 digital signatures have a major importance than manual for this reason section 45 A, 47 A has greater importance. An expert opinion is not questioned in the court of law unless the court finds any fraud. The most important expert opinion provided are of medical expert and ballistic expert particularly in a criminal case. This proves that how an opinion of an expert is necessary in judicial proceedings.

Bibliography:
Books:

1. Law of evidence by V.P.Sarathi
2. Law of evidence by Ratanlal and Dhirajlal

Bare act

1. Indian evidence act, 1872
2. Indian penal code, 1860
3. Indian divorce act, 1869
4. Information technology act

Websites:

• https://blog.ipleaders.in/expert-witnesses-under-the-indian-evidence-act-1872/
• https://indianlegalsolution.com/expert-opinion-and-its-relevancy/
• https://www.shareyouressays.com/knowledge/section-67-of-the-indian-evidence-act-1872/120456
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474433/