EVIDENCE 2.8 OPINION AND EXPERT EVIDENCE
Blacks’ Law Dictionary defines “expert evidence” as “evidence about a scientific, technical or professional issue given by a person qualified to testify because of familiarity with the subject or special training in the field”. BLD also defined “Opinion evidence” as “evidence as to a witness’s belief, thought or inference about a disputed fact”.
An expert was defined in AG Fed V Abubakar as any person specially skilled in the field he is giving evidence.
Section 67 makes opinion of persons to be generally irrelevant. This is correct because only the court has the power to draw conclusions. In ANPP V Usman, the court noted that “witnesses are called only to state facts and not to draw inferences from facts”. However, evidence or opinion of expert (especially scientific and empirical) can be given to assist the court in reaching the truth-ANPP above. E.g. opinion as to insanity, severity of injury, evaluation of certain, fingerprints, blood and DNA analysis, customary laws, scientific devices and other phenomena beyond the knowledge of the untrained-Seismograph Service V Esiso Akpororo.
Section 68 to 76 of the Act provide some instances where opinion of persons can be admissible.
- Forensic Expert Witness: can be used by the courts to obtain empirical evidence which is more credible and compelling. E.g. finger print, handwriting and DNA analysis. The disadvantage of FEOpinion is that their techniques may violate right of privacy, their experiments may be expensive, time consuming and prone to manipulation or errors which would produce inaccurate results.
The Responsibilities of the Expert Include:
- His evidence should be unbiased and independent:-Whitehouse V Jordan, Elf V Sillo.
- In R V Maguire, the court advised that the expert should not willingly/knowingly suppress a material fact… as such may lead to the quashing of conviction on appeal
- He should expressly surrender when the question falls outside his expertise/Knowledge-ANPP V Usman. Else it may amount to hearsay-Olalomi Industries V NDIC, Uwa Printers Limited V Investment Trust Company Limited.
- Where he is unsure or evidence unresearched, he should let the court know same-Re J. Derby and Co Ltd V Weldon and Others.
- The evidence should be unequivocal. In Akinfe V The State, the doctor did not say whether the poison (gamalin) administered to the deceased was what killed her. In Lori V State, the medical report gave cause of death to be “either asphyxia or poisoning”. In Umoru V State, medical evidence said it was either the slap or a head injury or cerebral insufficiency associated with HBP, old age and excessive intake of alchohol. In these cases, conviction secured on the evidences were quashed.
- His report should be complete, reasonable and should not contain fundamental flaws-Princewill V State. In Oladimeji V State, the medical report failed to link the examined corpse with the deceased and medical practitioner could not remember the name of the deceased. This resulted in a reduction in the weight attached to the doctor’s testimony. The medical evidence should not be contradictory-Kalu V State.
- If he changes his view on a material matter, he should timeously intimate/tell the court.
- The expert may be required to state or prove the grounds upon which his opinion is based-Arisa V State.
Note also that:
- Although the court is not meant to foolishly take the evidence of the expert “hook line and sinker”, it should however not unjustifiably substitute its own opinion for a credible and uncontroverted expert evidence-Ize-Iyamu V Alonge.
- The expert is entitled to refresh his memory from his report or by reference to professional treatises/books.
- Documents used should be provided to the opposite party at the same time as the exchange of reports.
- The adversary should be given the opportunity to cross-examine the expert witness and even challenge his qualification, experience or report at the trial-Azu V Ogundare.
- The Expert should tender the evidence personally or (in his absence), a written report bearing his signature can be tendered–SPDCN V Isaiah.
- The expert witness should be competent, diligent and specially skilled in the field he is giving evidence.-G Federation V Abubakah. It is not professional qualification but rather his experience and skill that matters-Damina V Akpan.
- Where there are conflicting expert opinion, the court can accept one and reject the other after proper evaluation-Egesimba V Onuzuruike, ANPP V Usman
- Opinion as to Relationships: Section 75 provides: When the court has to form an opinion as to the relationship of one person to another, the opinion expressed by conduct, as to the existence of such relationship of any person who, as a member of the family or otherwise, has special means of knowledge on the subject, is admissible.
- Expert On Foreign Law: From Section 68 and Section 69 Where there is a question as to foreign law, the opinions of experts acquainted with such foreign law are admissible-Ajani V Comptroller of Customs. Sonnar (Nig) Ltd V Partenreederi M.S. Nordwind. R V Bengert.
- Expert on Customary Law and Custom: Section 68 and 70 are instructive on this. Remember that customary law needs to be proved- Giwa V Erimilokun. Section 70 provides; In deciding questions of customary law and custom, the opinions of traditional rulers, chiefs or other persons having special knowledge of the customary law and custom and any book or manuscript recognised as legal authority by people indigenous to the locality in which such law or custom applies, are admissible.
The requirement of proof may not apply in a customary court except the presiding judge is not versed in the particular custom-Iyamuse Ehigie V Gregory Ehigie. This Section would also not apply where the custom has been registered or enacted in law.
- Expert on Handwriting: Section 68 and 72 are instructive on this. In Ize-Iyamu V Alonge the court noted that expert’s evidence can be admitted to decipher words beneath obliterations, erasures, alterations, nature of handwriting, and linking the handwriting to a person. See Salami V C.OP UTB V Awanziganu Enterprises 1994 6 NWLR pt 348 56.
In conclusion, forensic and expert evidence are of immense help in litigations. It is therefore important for stakeholders in the administration of justice to be trained on best practicesof applying forensic sciences to the Nigerian legislative framework
 Fidelis Nwadialo sees it as a conclusion reached from an evaluation of facts and circumstances based on one’s expert knowledge and understanding.
 Same definition in Damina V Akpan, Azu V The State.
 Awaye Motors Company Limited V Adewunmi 1993 5 NWLR pt 292 236. Modupe V The State 1998 4 NWLR pt 87 130.
 Not only those of experts-Arisa V State. In Ejinima V State, the court noted that the surest way of proving insanity is by medical evidence (see also Kure V State, R V Inyang). However, insanity can also be deciphered from conduct (Loke V State, Sanusi V State R V Turner) evidence of relatives, evidence of family history (Loke V State), traditional healer (Mohammed V State).
 See Dawodu V Danmole, where the Idi Igi custom was proved.
 See for example Idudhe V Eseh 1996 5 NWLR pt 451where expert witness testified that grinding machine made excessive noise.
 Guaranteed under Section 37 of the 1999 Constitution. E.g. planting bugging devices, taking blood and dna samples and so on.
 See also the Dictum of Mr Justice Cresswell in National Justice Compania Naviera SA V Prudential Assurance Company Ltd 1993 Lloyds Rep 68 where he listed the obligations and duties of the expert.
 Polivitte Ltd V Commercial Union Assurance Co plc 1987 Lloyd’s Rep 376 at p 386 = pr Mr Justic Garland
 Re J 1990 FCR 193 per Mr Justice Cazalel.
 1981 1 WLR 246 at p 356 per lord Wilberforce..
 Dickson Arisa V The State 1987 7 SCNJ pt 1 76 at 84.
 Mohammed V State, Whitehouse V Jordan.
 A.G Federation V Ogunro (2001) 10 NWLR pt 720.
 1994 6 NWLR Pt 353 703 at 713.
 Damina V The State, a witness called the deceased Bargo while the report called the deceased Audu. The court held (relying on Princewill V State) that since no evidence was adduced to show that Bargo and Audu are one and the same person, the medical report was worthless.
 In ANPP V Usman, the court noted that opinion of experts should be taken with a pinch of salt-Waziri V State… meaning that the court should be circumspective and ensure that the expert has not be bought by the party.
 AG Oyo State V Fairlakes Hotels (No. 2)
 Section 239(2) EA. Oladimeji V State. Chukwu V State the expert was allowed to refresh his memory by looking at his report.
 Section 239.
 1993 7 scnj pt 1 150.
 AG Fed V Ogunro.
 Audu V State.
 Nwachukwu V State (the expert Dr. Ihuzue had travelled overseas for further studies and his location abroad was unknown and the date of his return was unknown. The medical report was admitted as the court noted it did not have to wait for him. Same conclusion was reached on similar facts in Eyo V State, Edoho V State, Oguno V State. It all depends on the fact of the case-Adeoti V State.
 1997 6 NWLR pt 508 236.
 2007 All FWLR pt 375.
 2011 All FWLR pt 580 1298 CA. Arewa Textiles Plc V Finetex Limited (managing director who had worked in textile industry for over 20 years was an expert in the textile industry). See also Seismograph Services Ltd V Onokpasa. Aigbaton V State. Said Ajani V Comptroller of Customs 1952 14 WACA 34. A bank manager with over thirty years bank working experience was called as expert to ascertain which currency was legal tender in French-West Africa. Same point has been noted in SPDCN Ltd V Adamkwe, Uniperol Nig Plc V Adireje W/A Limited. Ara-Nde V Queen.
 2002 FWLR pt 128
 2011 All FWLR Pt 463 1292 CA.
 Ojemen V Momodu. Here members of the Irrua community with special knowledge in their customary law were competent witnesses on the issue. See also Queen ex parte Epenga V Ozogula II.
 In Ibrahim V Barde, “Abuja Chronicle” which was generally regarded by the Suleja people as authority on their native law and custom was admitted. In Adeseye V Taiwo, A.K Ajisafe’s Laws and Customs of the Yoruba was also admitted to prove. Onwuchekwa V Onwuchekwa too “The Customary Law Manual 1977” was admitted to find a point of law. However, in Idundun V Okumagba, the court held that evidence should be adduced to show that the book is generally acknowledged. The author of the treatise should be called except the author is dead or cannot be found or incapable of giving evidence or cannot be called without unreasonable delay.
 Queen ex parte Epenga V Ozogula II.
 2007 All FWLR pt 371 1570 C.A.
 See also R V Onitiri 1946 12 WACA 58. Where the analysis of police officer received. Olowu V Building Stock Ltd.
 Note the Daubert Standard.