1. The Law in Nigeria
1.1 Relevant Statutory Provisions
Section 14 Evidence Act 2011
Evidence obtained –
(a) improperly or in contravention of a law; or
(b) in consequence of an impropriety or of a contravention of a law, shall be admissible unless the court is of the opinion that the desirability of admitting the evidence is out-weighted by the undesirability of admitting evidence that has been obtained in the manner in which the evidence was obtained.

Section 15 Evidence Act
For the purposes of Section 14, the matters that the court shall take into account include –
(a) the probative value of the evidence;
(b) the importance of the evidence in the proceeding;
(c) the nature of the relevant offence, cause of action or defence and the nature of the subject-matter of the proceeding;
(d) the gravity of the impropriety or contravention;
(e) whether the impropriety or contravention was deliberate or reckless;
(f) whether any other proceeding (whether or not in a court) has been or is likely to be taken in relation to the impropriety or contravention; and
(g) the difficulty, if any, of obtaining the evidence without impropriety or contravention of law.

1.2 Case Law before 2011
Formerly, and in the absence of any statutory provisions, Nigerian courts followed the English judicial authorities on the point. In Sadau v The State, the Supreme Court held that, while there was no general rule of law that evidence which was relevant may be excluded by the way it was obtained, a Judge may, in the interest of justice, exclude evidence which would otherwise be relevant considering the circumstances of its discovery and production. This author is not aware of any reported case in Nigeria where this judicial discretion to exclude prejudicial evidence has ever been exercised. However, in view of the new provisions of section 14 and 15 of the Evidence Act, it is hoped that the Supreme Court will soon be presented with an opportunity to pronounce on this important point.

There are two earlier decisions of the Supreme Court on the judicial discretion to exclude relevant evidence. In Sadau (supra), the defendant was charged with illegal printing and selling of vehicle licences. A search warrant executed at his house led to the discovery of a large quantity of forged documents. The Supreme Court held that the incriminating evidence was relevant and admissible even though the search warrant was improperly executed. It is submitted, that if a similar case arose today and the court were to apply the provisions of section 14 and 15 of the Evidence Act, the evidence would still be admissible because the importance of the evidence outweighed the gravity of the impropriety. See sections 15(b) and 15(d) of the Evidence Act. However, if the search was conducted without a warrant the evidence would have been inadmissible.

In Igbinovia, a detective was planted in the same cell with the defendant who boasted that he committed the offence. Counsel argued that the oral confession should be rejected because it was prejudicial having regard to the circumstances in which it was obtained but the Supreme Court held that the confession was admissible. Eso JSC said that, there is no defence of entrapment under Nigerian criminal law. Again, it is submitted that if a similar case arose today and the court were to apply the provisions of section 14 and 15 of the Evidence Act, the evidence would still be admissible as the court will recognise the difficulty of obtaining the evidence without the deception. See section 15(g) of the Evidence Act.

Evidence of Agent Provocateurs
Police officers who act as agent provocateurs should not to be regarded as accomplices whose evidence requires corroboration. However, they are tainted witnesses with a purpose to serve and as such their evidence must be treated with caution. In Akinlemibola v The State, the appellant was convicted of official corruption. The case of the prosecution was that the appellant demanded a bribe before he could perform his official duties and a police trap was set where he was given marked currency notes. The question was whether the prosecution witnesses (police officers) were accomplices to the offence. The Supreme Court held that the police officer who set the trap was personally involved in the matter as he was the applicant for a motor vehicle loan. Since he gave the bribe, he too had committed the offence of official corruption and was therefore an accomplice whose evidence should have been corroborated. The Supreme Court also disapproved of “state-created” offences by agent provocateurs. Fatayi-Williams JSC said,
“In this connection, we refer, with approval, to the observation of Parker LCJ in The Queen v. Birtles: – “It is vitally important to ensure as far as possible that the informer does not create an offence, that is to say, incite others to commit an offence which those others would not otherwise have committed. It is one thing for the police to make use of information concerning an offence that is already laid on. In such a case, the police are clearly entitled, indeed it is their duty, to mitigate the consequences of the proposed victim, and to that end it may be perfectly proper for them to encourage the informer to take part in the offence or indeed for a police officer himself to do so. But it is quite another thing, and something of which this court thoroughly disapproves, to use an informer to encourage another to commit an offence or indeed an offence of a more serious character, which he would not otherwise commit, still more so if the police themselves take part in carrying it out.”

In official corruption cases, the person who gives a bribe may not always be a willing participant but may actually be a victim of extortion and in such cases the victim will not be regarded as an accomplice. In Nwanchi v State, the appellant, a policeman, was convicted of accepting gratification. On the first count, the case of the prosecution was that a complaint of stealing was made against pw3 who was arrested and detained by the appellant but released on bail three days later only after an agreement to pay gratification to the appellant. On the second count, the case of the prosecution was that a sheep was stolen and later found in the house of pw6 who was arrested and detained but released later the same day only after an agreement to pay gratification to the appellant. The Supreme Court held that pw3 and pw6 were victims and not accomplices because they paid the gratification under duress. Obaseki JSC said,
“A person who, under duress, pays money in response to an unlawful demand is not an accomplice in the demand. …. A witness to such payment cannot by any stretch of the imagination and the authorities be an accomplice. We are of the view that a person who pays money in response to an unlawful demand when he has committed no offence and charged with none, is not an accomplice in the acceptance. He did not deliberately offer the cash to corrupt.”

1.3 Sections 14 & 15 Evidence Act
Section 14 of the Evidence Act states that evidence obtained improperly or in contravention of a law or in consequence of an impropriety or of contravention of a law shall be admissible but may be excluded where the court is of the opinion that the desirability of admitting the evidence is outweighed by the undesirability of admitting the evidence. Section 14 of the Act is statutory authority for judicial discretion to exclude relevant evidence where the prejudicial effect outweighs the probative value of the evidence or where the admissibility of the evidence will be unfair to the defendant. It is submitted, that in addition to the authority of section 14 of the Act, the judicial discretion to exclude relevant evidence which is prejudicial or unfair to the defendant can also be exercised under the constitutional duty of all courts to ensure that every defendant gets a fair trial. See section 36(4) of the Constitution FRN.

Furthermore, on the authority of section 14 of the Act, evidence obtained in breach of the provisions of the Constitution FRN and the fundamental rights of a defendant may be inadmissible. Section 37 of the Constitution FRN, protects citizens against the invasion of privacy and states that, “The privacy of citizens, their homes, correspondence, telephone conversations and telegraphic communications is hereby guaranteed and protected.” In Enyinnaya v The State, policeman raided the house of a native doctor without a search warrant and killed one person. Agim JCA said,
“The invasion of the house of the native doctor (Chibuike) is unlawful as it violates his fundamental human right to the privacy of his person and his home guaranteed him by S.37 of the 1999 Constitution of Nigeria. …… Privacy at its most fundamental level is the right to be left alone. This suggests that a zone surrounds every individual within which he or she should be protected from intrusion by others. It is the most valuable of all rights.”

By virtue of section 15 of the Evidence Act courts are obliged to take into account certain matters to determine whether the desirability of admitting the evidence in question is outweighed by the undesirability of admitting the evidence. They include; the probative value of the evidence; the importance of the evidence in the proceedings; the nature of the relevant offence; cause of action or defence and the nature of the subject-matter of the proceeding; the gravity of the impropriety or contravention; whether the impropriety or contravention was deliberate or reckless; whether any other proceeding has been or is likely to be taken in relation to the impropriety or contravention; and the difficulty of obtaining the evidence without impropriety or contravention of the law.

The proper time to challenge the propriety of the evidence is at the time
the evidence is about to be presented or tendered. In Onyuike v People of Lagos State, the defendant sought to quash the charges before arraignment and argued inter alia that the evidence was improperly obtained. Dongban-Mensem JCA said,
“The appropriate time to take objection to improperly or illegally obtained evidence is at the hearing of the case when the prosecution applies to put in evidence the improperly or illegally obtained evidence.”

Exclusion of Confessional Statements
Apart from the provisions on the admissibility of improperly obtained evidence contained in sections 14 and 15 of the Evidence Act, the only other similar statutory provision can be found in section 29 of the Evidence Act which provides for the exclusion of confessional statements which are made under oppression or in circumstances which make the confession reliable. When a confession is tendered in evidence by the prosecution the defendant can object to the admissibility of the confession. One ground of objection is that the confession was improperly obtained. Therefore, even where a confession is admissible under section 29 of the Evidence Act the court still has a discretion to exclude the confession under section 14 Evidence Act on the grounds that the confession was obtained in consequence of an impropriety or in contravention of any law.

The failure to properly caution the defendant about the right to remain silent during interrogation and before the confession was obtained will be a valid ground for the challenging the reliability of a confession. See section 35(2) of the Constitution. A violation of the constitutional rights of the defendant may also render a confession inadmissible under section 14 of the Evidence Act. Any procedural failures or breach of the rules of custodial interrogation can form the basis for challenging the admissibility of a confession on the ground of unreliability under section 29(2)(b) of the Evidence Act.

Section 30 of the Evidence Act states that, where information is received from a suspect and in consequence of such information any fact is discovered, the discovery of the fact, together with evidence that such discovery was made in consequence of the information received from the defendant, may be given in evidence where such information itself would not be admissible in evidence. This means that any relevant incriminating fact, discovered as a result of information received through an inadmissible confession, will be admissible in evidence. However, such evidence can still be excluded under section 14 of the Evidence Act.

2. The Law in other Jurisdictions
Foreign rules of evidence are not part of the law of evidence in Nigeria. See sections 2 and 3 of the Evidence Act 2011. Therefore, any foreign rule of evidence which prohibits or excludes any evidence against a defendant, whether obtained improperly or unfairly, cannot be part of the law of evidence in Nigeria. However, the paucity of judicial decisions in Nigeria on the exclusionary principle of evidence contained in sections 14 and 15 of the Evidence Act require the search for persuasive judicial authority from foreign jurisdictions. In USA the emphasis is on the unconstitutionality of the violation but in England the emphasis is on the effect of the violation on the fairness of the proceedings.

2.1 England
Section 78(1) of the Police and Criminal Evidence Act
In any proceedings the court may refuse to allow evidence on which the prosecution proposes to rely to be given if it appears to the court that, having regard to all the circumstances including the circumstances in which the evidence was obtained, the admission of the evidence would have such an adverse effect on the fairness of the proceedings that the court ought not to admit it.

At common law the courts developed a judicial discretion to exclude relevant evidence which was obtained improperly and to exclude admissible evidence when the prejudicial effect against the defendant outweighed the probative value of the evidence. In England this judicial discretion to exclude unfair evidence was codified in section 78(1) of the Police and Criminal Evidence Act 1984. Some authorities are helpful to explain the application of this statutory judicial discretion. In Mason, after his arrest the defendant was told by the police that his fingerprint had been found on glass from the crime scene. Upon hearing this false information the defendant confessed and was convicted of arson. The Court of Appeal quashed the conviction and held that the trial judge should have excluded the confession because of the deception practiced on the defendant.

In Bailey, the defendants were later placed together in the same cell which was bugged. The Court of Appeal held that evidence of incriminating conversation between the defendants was admissible despite the use of this trick by the police. In Khan, the House of Lords upheld the decision to admit evidence obtained from surveillance devices which had been placed on the premises of the defendant. In Smurthwaite, the defendants were convicted of soliciting murder. The person solicited was an undercover police officer posing as a contract killer and the prosecution relied upon secret tape recordings of meetings held between the police officer and the defendants. The Court of Appeal upheld the decision of the trial judge not to exclude the evidence. In Williams v DPP, the police during investigation into stealing from vehicles, parked a vehicle with valuable goods on a busy street. Police officers on surveillance later observed the defendant removing goods from the vehicle. The Court of Appeal held that the magistrate was entitled to admit the evidence against the defendant because no one in particular was targeted and the police officers were not acting as agent provocateurs.

One important discussion in England, which is relevant to Nigeria, is whether in view of the provisions of section 78 of the Police and Criminal Evidence Act, the defence of entrapment is available under English law and whether courts have the discretion to exclude evidence on the ground that the offence was instigated by an agent provocateur. The decision of Sang, stated the position before the Police and Criminal Evidence Act 1984. In that case, the House of Lords held that courts had no discretion to exclude evidence of an offence on the ground that it was instigated by an agent provocateur since there was no defence of entrapment in English law.

The case of Loosely (AG’s Reference No.3), stated the position after 1984. The House of Lords held that, although there was no defence of entrapment in English law, evidence of entrapment is an abuse of process and the evidence obtained may be excluded because police conduct which brings about “state-created” offences is unacceptable and improper. The court held that the overall consideration should always be whether the conduct of the police was so improper as to bring the administration of justice into disrepute.

2.2 United States of America
4th Amendment, Constitution of the United States
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Rule 403 Federal Rules of Evidence
The court may exclude relevant evidence if its probative value is substantially outweighed by the danger of one or more of the following: unfair prejudice, confusing the issues, misleading the jury, undue delay, wasting time, or needlessly presenting cumulative evidence.

In the United States of America the courts are concerned with the method by which evidence is obtained and evidence obtained in breach of the constitutional rights of the defendant is regarded as inadmissible. The law was settled in the case of Mapp v Ohio, where the police conducted an unlawful search and seizure on the premises of the defendant and recovered incriminating documents. The Federal Supreme Court held that evidence obtained by unlawful searches and seizures in violation of the constitutional rights of the defendant under the Fourth Amendment was inadmissible. Justice Clark cited with approval the dictum from the case of Weeks v United States,
“If letters and private documents can thus be seized and held and used in evidence against a citizen accused of an offence, the protection of the Fourth Amendment declaring his rights to be secure against such searches and seizures is of no value, and so far as those thus placed are concerned, might well be stricken from the Constitution. The efforts of the courts and their officials to bring the guilty to punishment, praiseworthy as they are, are not to be aided by the sacrifice of those great principles established by years of endeavour and suffering which have resulted in their embodiment in the fundamental law of the land.”

In Katz v US, the exclusionary principle was extended to evidence obtained by listening devices (wiretapping and eavesdropping). In that case, the defendant used a public phone booth for illegal activities. The FBI recorded his conversations by means of an electronic listening device attached to the phone booth and the conviction was based on these conversations. The defendant argued that the recordings were a violation of his Fourth Amendment rights which protects the privacy of citizens against unreasonable search and seizure. The Federal Supreme Court held that an electronic intrusion into any place that is private may constitute a violation of the Fourth Amendment. Justice Stewart said,
“The Government’s activities in electronically listening to and recording the petitioner’s words violated the privacy upon which he justifiably relied while using the telephone booth and thus constituted a ‘search and seizure’ within the meaning of the Fourth Amendment.”

However, evidence obtained by the use of a device, like a microphone secretly carried or attached to any person, to tape conversations with a suspect, is admissible because it does not involve an invasion of privacy. In Carpenter v United States, the appellant was convicted of robbery and the prosecution relied on evidence of his mobile phone location. The United States Supreme Court in a split decision (5:4) held that access to the mobile phone location records of a suspect without a search warrant was a violation of his Fourth Amendment rights. The United States Supreme Court also held that the search of the mobile phone of a suspect during arrest without a warrant was a violation of his Fourth Amendment rights.

Jide Bodede LLM(Lond). Author of Criminal Evidence in Nigeria, 2ed 2022.