Introduction
The law of evidence occasionally confronts a rather uncomfortable question: What should a court do with perfectly useful evidence obtained by perfectly unlawful means?
Suppose the police enter Naa Sarku’s house unlawfully and discover ten bags of suspected cocaine under her bed. Or suppose Tope secretly records Adu-Boahen admitting during a telephone conversation that he forged a document. Or, more dramatically, suppose Adusanana unlawfully accesses a suspect’s telephone, discovers a WhatsApp message saying, “The stolen goat is behind Uncle kpem’s kitchen,” proceeds there, and actually finds the unfortunate goat staring innocently at the her.
The goat is real. The message is real. The crime may also be real.
But the route by which the authorities arrived at the goat may have been unlawful.
Must the court pretend that the goat does not exist?
That, stripped of its botanical language, is the problem underlying the celebrated doctrine known as the “fruit of the poisonous tree.”
The expression is associated particularly with American constitutional criminal procedure. Its essential proposition is simple: where the source—the “tree”—from which evidence has been obtained is constitutionally or legally contaminated, evidence subsequently derived from that illegality—the “fruit”—may itself become tainted.
Ghanaian law, however, requires considerably more nuance. The 1992 Constitution, the Evidence Act, 1975 (NRCD 323), and particularly the Supreme Court decision in Raphael Cubagee v Michael Yeboah Asare & Others [2018] GHASC 14, point not towards an inflexible American-style rule of automatic exclusion, but towards a discretionary constitutional approach in determining whether evidence obtained through violation of a constitutional right should be admitted.
The poisonous tree may therefore grow in Ghana. But, strangely enough, not every fruit hanging from it must necessarily be thrown away. In this paper, the author navigates the dynamic and forward looking ghanaian approach and application of the principle and how nuanced it can be especially for the practitioner and the judge.
1. Where Did This Poisonous Tree Come From?
The metaphor has its roots in American constitutional jurisprudence.
In Silverthorne Lumber Co v United States 251 US 385 (1920), the United States Supreme Court dealt with the consequences of information obtained through unlawful governmental conduct. The principle subsequently developed into what became known as the “fruit of the poisonous tree” doctrine. The expression itself became particularly associated with Nardone v United States 308 US 338 (1939).
The logic is attractive. If the Constitution prohibits the State from obtaining evidence through a particular unlawful method, it would considerably weaken that protection if the State could nevertheless exploit everything discovered as a direct consequence of the violation.
Thus: Illegal search → discovery of key → key opens warehouse → warehouse contains stolen goods.
The prosecution cannot necessarily cleanse the stolen goods simply by saying: “My Lord, forget about how we found the key. Kindly concentrate on the warehouse.”
The doctrine asks the court to examine the causal relationship between the original illegality and the subsequent discovery. The metaphor therefore distinguishes between: The poisonous tree — the original unlawful or unconstitutional investigative act; and The poisonous fruit — evidence discovered as a consequence of that act.
American law has developed qualifications to the doctrine, including concepts such as independent source, inevitable discovery and attenuation of the connection between the original illegality and the evidence ultimately obtained. The doctrine is therefore more sophisticated than the proposition that “once illegality occurs, everything thereafter disappears.”
2. The Traditional Common-Law Approach: “It Matters Not How You Get It”
The traditional English common-law approach was considerably less sentimental about poisoned vegetation. The often-cited statement of Crompton J in R v Leatham (1861) 8 Cox CC 498 was essentially that it mattered not how evidence had been obtained—even if it had been stolen—provided it was otherwise admissible. The philosophy was straightforward. The trial court was principally concerned with whether the evidence was relevant and reliable, rather than with disciplining the person who improperly obtained it.
On that reasoning, if a police officer Vlad, illegally entered a room and found the murder weapon, the officer might have committed an actionable or punishable wrong, but the knife did not mysteriously cease to be a knife. The illegality committed by the policeman and the evidential value of the knife were conceptually separate questions and one might put the traditional common-law position rather mischievously: “Arrest the policeman later. For now, bring the knife.”
Ghanaian law of evidence historically inherited important elements of this common-law emphasis upon relevance. But the 1992 Constitution, with its entrenched fundamental rights, substantially complicates any simplistic application of the old rule.
3. The Starting Point Under Ghana’s Evidence Act
The statutory starting point is the Evidence Act, 1975 (NRCD 323). Section 51 embodies the general principle that relevant evidence is admissible except where an enactment provides otherwise. Section 52, however, gives the court power in appropriate circumstances to exclude relevant evidence, including where its probative value is substantially outweighed by specified countervailing considerations.
Consequently, relevance is enormously important under Ghanaian evidence law. But relevance is not an immigration officer carrying a diplomatic passport. Evidence does not necessarily enter the courtroom merely by announcing: “Good morning, My Lord. I am relevant.” Other constitutional and statutory principles may still stop it at the border.
That qualification became particularly important with the Supreme Court’s decision in Cubagee v Asare. The Court expressly considered sections 51 and 52 in addressing evidence obtained through infringement of a constitutionally guaranteed right.
4. Enter the 1992 Constitution
Several constitutional guarantees potentially affect the manner in which evidence is obtained. Article 15 protects human dignity and prohibits torture and cruel, inhuman or degrading treatment or punishment. Article 18(2) protects the privacy of the home, property, correspondence and communication against interference except in circumstances permitted by the Constitution. Article 19 contains important fair-trial guarantees.
These provisions read as a whole guarantees that investigative convenience cannot automatically trump constitutional rights. A police investigator Hilda, cannot reasonably say: “My Lord, we knew Article 18 existed, but the suspect’s password was very difficult, so we decided that constitutional law should wait until Monday.”As all lawyers are aware from Kumado 101, The Constitution does not go on weekend leave.
At the same time, constitutional rights themselves operate within a constitutional framework. Article 12(2) expressly recognises that fundamental rights are enjoyed subject to respect for the rights and freedoms of others and the public interest. It is this interaction between individual rights, evidential truth, fairness and the public interest that lies at the heart of the Ghanaian position.
5. Raphael Cubagee v Michael Yeboah Asare: Ghana Meets the Poisonous Tree
The leading modern Ghanaian authority is Raphael Cubagee v Michael Yeboah Asare & Others [2018] GHASC 14, decided by the Supreme Court on 28 February 2018. In that case, the plaintiff sought to tender an audio recording of a telephone conversation involving a representative of one of the defendants. The difficulty was that the conversation had been secretly recorded without the other participant’s knowledge. An objection was raised that the recording violated the constitutional right to privacy guaranteed by article 18(2).
When the matter eventually reached the Supreme Court by constitutional reference, the Court held that secretly recording the telephone conversation in the circumstances of the case constituted an interference with the other participant’s privacy beyond the scope of what he had consented to merely by participating in the telephone conversation.
That conclusion was important. But what followed was even more important for the law of evidence. The Court did not establish the proposition that every piece of evidence obtained through every illegality is automatically inadmissible. Instead, the Supreme Court adopted for Ghana a discretionary approach to evidence obtained in violation of constitutionally guaranteed human rights.
The question is therefore not merely: Was the evidence unlawfully obtained? The court must also consider whether, having regard to the circumstances, admission or exclusion is appropriate, particularly considering the fairness and integrity of judicial proceedings and the public interest. That distinction is fundamental.
6. Cubagee Is Not an Automatic Exclusionary Rule
This deserves emphasis because Cubagee is sometimes reduced to the proposition that: “Secret recording = inadmissible.” That formulation is too broad. The larger jurisprudential contribution of Cubagee is its balancing approach.
The Supreme Court recognised considerations including the nature of the constitutional right infringed, the nature and seriousness of the violation, whether the violation was deliberate or innocuous, and—in criminal proceedings—the gravity of the offence, its manner of commission and the punishment attached to it. The overarching concern includes whether admission of the evidence would adversely affect the fairness or integrity of proceedings or bring the administration of justice into disrepute. Thus Ghana has not simply transplanted the American exclusionary rule. The Ghanaian judge remains a constitutional goalkeeper.
7. A Very Ghanaian Example: The Missing Goat
Consider the following entirely imaginary proceedings: Republic v Kwame Mensah — The Missing Goat Case
A goat belonging to Mr Asampoa disappears from Ho. The police suspect John Bald. Without lawful authority, an officer enters John’s bedroom finds and searches his mobile phone.
He discovers the following WhatsApp message: “Chairman, tie Asampoa’s goat behind Auntie Jessica’s chop bar before sunrise.”The police proceed immediately to Auntie Jessica’s chop bar. Behind the kitchen stands the goat. For reasons known only to itself, the goat says nothing about how it got there.
During the trial before Justice Oworae, the prosecution seeks to tender:
- the WhatsApp message;
- photographs of the goat;
- evidence of the police officers who recovered it; and
- possibly the goat itself, assuming courtroom security can accommodate it.
Under a strict fruit-of-the-poisonous-tree approach, counsel for accused Saaka argues that the unlawful telephone search was the poisonous tree and that the discovery of the goat was its fruit. Therefore “My Lord, the goat is constitutionally poisoned.” Under the Ghanaian approach, the analysis cannot end with that entertaining proposition: The court would have to examine the nature of the initial violation, its relationship to the subsequently obtained evidence, applicable statutory rules, the constitutional interests involved, fairness, public interest and the integrity of judicial proceedings. It will therefore be safe to state that the goat’s evidential future depends upon constitutional analysis rather than veterinary medicine.
8. Direct Evidence and Derivative Evidence Must Be Distinguished
This is another important point. Cubagee concerned the very evidence obtained through the constitutional violation: the secretly recorded conversation. The classical fruit-of-the-poisonous-tree problem does go one step further. It asks what happens to derivative evidence subsequently discovered because of the original illegality.
Suppose an unlawful interrogation produces:
“The gun is buried under the mango tree at Aburi.” Police subsequently recover the gun. There are now at least two analytically different pieces of evidence: First: the unlawfully obtained statement. Second: the physical weapon discovered because of that statement. The second is the metaphorical “fruit.”
The Ghanaian Supreme Court in Cubagee did not simply enact the entire body of American derivative-evidence jurisprudence into Ghanaian law. It is therefore safer to say that Cubagee supplies a powerful constitutional framework within which such questions may be addressed rather than to assert that Ghana has adopted wholesale the American doctrine. Indeed, Ghanaian commentary has appropriately characterised the post-Cubagee position as one under which a poisonous tree may, in appropriate circumstances, produce evidence that is nevertheless admitted.
9. The Secret Recording Problem
Consider another hypothetical.
Ramatu suspects her husband, Michael, of secretly selling family land.
She telephones him and says: “Mike, did you really sell the East Legon land?”
“Yes. I sold it. Replies Michael. I used GH¢500,000 to buy a Range Rover, GH¢200,000 to start a business, and the remaining GH¢300,000 is safe.” Ramatu asks: “Safe where?” Mike replies: “Very safe. Nobody can touch it.” She later discovers that “very safe” meant that Michael had given it to his mother.
Unfortunately for Michael, Ramatu recorded the entire telephone conversation without informing him.She arrives in court triumphantly carrying the recording as though Moses has just descended from Mount Sinai with Exhibit A.
Michael’s counsel Crabbe rises: “Objection My Lord, Cubagee v Asare.” Ramatu’s smile immediately becomes a constitutional question. The court must determine, among other matters, whether the recording involved an infringement of privacy and then address admissibility under the constitutional and evidential principles explained in Cubagee.
The fact that Michael may indeed have said everything alleged does not, by itself, answer the admissibility question. Truth is important. But constitutional adjudication occasionally asks another question: At what price was the truth obtained?
10. The Police Officer Who “Accidentally” Searches Everything
Suppose the police obtain lawful authority to search Gabo’s Mercedes for a stolen laptop.
They search the boot. No laptop. They search underneath the seats. Still no laptop. One particularly enthusiastic officer Nelson, then announces: “My Commander, laptops these days are very advanced.” He proceeds to search Gabo’s bedroom, kitchen, bathroom, mother’s wardrobe and eventually the ceiling of the family house. Inside the ceiling he finds cocaine.
The prosecution cannot answer an objection merely by saying: “But My Lord, cocaine was actually there.” The existence of evidence and the legality of obtaining it are distinct questions. The Ghanaian court would have to consider the lawful scope of the search, the constitutional rights implicated, the seriousness and manner of the violation and the broader considerations identified in Cubagee. Otherwise, a warrant to search for one laptop could become a judicial visa to tour the entire Republic of Ghana.
11. Torture Presents an Even More Serious Case
The constitutional stakes become considerably higher where evidence is obtained through torture, violence, coercion or degrading treatment. Article 15’s protection of dignity and prohibition of torture reflects values fundamental to constitutional government.
Imagine:
Rockson, a suspect, refuses to disclose the location of stolen money.
An investigator from EOCO assaults him until he says: “Please stop! The money is underneath my wife’s bed.” The police go there and recover GH¢2 million. Wifey, who previously believed the mysterious suitcase contained old church cloth, nearly required medical attention for her shock.
The evidential issue is serious.There may be questions concerning both the admissibility of the compelled statement and the status of physical evidence discovered because of it. Confession evidence also attracts specific statutory safeguards under section 120 of Ghana’s Evidence Act.
The constitutional concern here is considerably more severe than an innocent procedural irregularity. A legal system that routinely rewards torture with admissible evidence risks creating a perverse incentive: Beat first; investigate later. That would be difficult to reconcile with the constitutional commitment to dignity and the integrity of justice.
12. The Difference Between an Illegality and a Constitutional Violation
Another distinction is necessary. Not every irregularity in obtaining evidence necessarily constitutes a violation of a fundamental human right.
There may be:
- breaches of constitutional rights;
- breaches of statutory requirements;
- procedural irregularities;
- breaches of administrative directions;
- private wrongdoing; and
- mere imperfections in investigation.
The legal consequences need not necessarily be identical. Cubagee is particularly authoritative concerning evidence obtained through violation of constitutionally protected human rights. Courts should therefore identify precisely what made the evidence “poisonous.”
Calling something “illegally obtained” is the beginning of the analysis, not its conclusion. Counsel must identify the poison. Otherwise, every evidential objection may eventually become: “My Lord, we do not like how they obtained it.” And “I do not like it” is not part of the enactment in section 53 of the Evidence Act.
13. Factors a Ghanaian Court Should Consider
Drawing particularly upon Cubagee, a Ghanaian court confronted with allegedly tainted evidence should logically ask:
First, what constitutional, statutory or legal rule was violated?
Second, whose right was violated?
Third, what was the nature and seriousness of the violation?
Fourth, was the violation deliberate, reckless, negligent or innocent?
Fifth, how directly did the violation produce the evidence?
Sixth, how important and reliable is the evidence?
Seventh, particularly in criminal proceedings, how serious is the offence and what interests of victims and society are implicated?
Eighth, was the evidence obtainable through an independent lawful source?
Ninth, would admitting the evidence encourage constitutional violations by investigators or private actors?
Tenth, conversely, would excluding highly reliable evidence disproportionately impair the administration of justice?
And ultimately:
Eleventh, Would admission or exclusion better preserve the fairness, integrity and reputation of the administration of justice?
This is not mechanical arithmetic. So one cannot say: Privacy violation = minus 5. Murder = plus 10. Cocaine = plus 7. Therefore admissible by twelve points. Judicial discretion is not the Ghana Premier League table. It requires principled evaluation of the circumstances of each case.
14. The Independent-Source Problem
Suppose an unlawful search of Boama’s telephone reveals that stolen machinery is located in Warehouse 14. But before that unlawful search occurred, an independent witness had already given police a statement identifying Warehouse 14, and a properly obtained CCTV recording independently pointed to the same location. Even jurisdictions applying the fruit-of-the-poisonous-tree doctrine recognise the conceptual importance of an independent source. Why? Because the law need not place the prosecution in a worse position merely because unlawful conduct occurred if the evidence genuinely came from an independent lawful route. Returning to Ghanaian horticulture: If the mango did not actually grow on the poisonous tree, counsel should not paint it with poison merely because both trees happen to stand in the same garden.
15. Inevitable Discovery
Consider a missing body buried beside a major road.
Blagogee, a police unlawfully obtains information identifying the location. However, at that very moment, a properly organised search party is moving systematically towards precisely the same location and would inevitably have discovered the body within minutes.
American jurisprudence has developed the “inevitable discovery” doctrine to address such circumstances. Whether and to what extent ghanaian courts should expressly develop an analogous principle within the Cubagee framework remains an interesting jurisprudential question. The underlying issue would remain whether exclusion genuinely vindicates constitutional rights and judicial integrity or instead places the administration of justice artificially in a position unrelated to the actual effect of the violation.
16. Attenuation: When the Poison Becomes Too Remote
Causation also matters.
Suppose an unlawful search occurs today in Hawa’s house.
Six months later, through an entirely separate investigation, Sekyiwa, a witness voluntarily comes forward and produces documents implicating Hawa. Her counsel Delor, cannot simply stand up and announce: “My Lord, six months ago the police behaved unlawfully in searching that house therefore everything that occurs after that date is in respect of the same house is poisonous.”
Even poison requires a delivery mechanism. The more remote the connection between the constitutional violation and subsequently discovered evidence, the weaker the argument that the later evidence is truly its “fruit.” This is the logic behind the American concept of attenuation.
Although Ghanaian courts need not mechanically import American terminology, questions of causation, remoteness, fairness and constitutional integrity fit comfortably within the discretionary approach recognised in Cubagee.
17. Private Citizens Are Not Licensed to Become the National Security Apparatus
Cubagee is particularly interesting because the constitutional problem did not arise from the stereotypical police search. It involved a private individual’s secret recording. This matters enormously in the smartphone age.
Almost every Ghanaian now carries in his pocket a device capable of becoming:
- a camera;
- a tape recorder;
- a tracking device;
- an archive;
- a surveillance system; and
- occasionally, judging from family WhatsApp groups, an unofficial Commission of Inquiry.
Technology has democratised surveillance. The constitutional challenge is therefore no longer simply: How should courts control the police? It is also: What happens when citizens obtain evidence against each other through invasions of constitutionally protected privacy?
Cubagee provides an important answer: technological convenience does not abolish constitutional rights. The fact that Okpoti’s iPhone has a red “record” button does not mean Article 18(2) has been repealed.
18. Social Media and the New Poisonous Orchard
Modern evidence increasingly consists of: WhatsApp messages, screenshots, secretly recorded Zoom meetings, CCTV footage, mobilemoney records, GPS information, emails, cloud backups, deleted messages and recordings. This creates new questions.
Suppose:
Quashiga unlawfully accesses Aima’s WhatsApp account and discovers photographs showing where stolen property is hidden.
Suppose the police subsequently recover the property.
The court may have to distinguish among:
- the unlawfully accessed WhatsApp material;
- information derived from it;
- physical evidence subsequently recovered;
- evidence independently obtained from another source; and
- evidence whose discovery has become sufficiently disconnected from the original constitutional violation.
That is precisely why the poisonous-tree metaphor remains useful even though Ghana has not adopted its strict American formulation. It forces judges and lawyers to think about evidential genealogy. Every important piece of disputed evidence should occasionally be asked: “Who is your father, and where exactly did you come from?”
19. The Doctrine Is About Courts Too
The exclusionary principle is sometimes misunderstood as a gift to accused persons. It is not. Its deeper concern is the legal system itself.
The question is whether courts should become beneficiaries of constitutional wrongdoing. If evidence obtained through serious violations is routinely accepted without consequence, constitutional guarantees may become impressive sentences hanging beautifully on courtroom walls but having little practical effect outside them.
On the other hand, automatic exclusion of every piece of reliable evidence following the smallest procedural irregularity could itself frustrate justice. Hence the wisdom of the Ghanaian discretionary approach. The court protects constitutional rights without deliberately becoming blind to reality.
20. A Final Hypothetical: The Case of the Missing Waakye
Perhaps the doctrine can finally be explained through breakfast.
At 7:00 a.m., Justice Yaw Pee buys waakye and leaves it in the judges’ common room. At 7:15 a.m., the waakye disappears. Suspicion immediately falls upon Dornyo the clerk.
Without permission, Israel, the registrar secretly accesses the clerk’s telephone and discovers a message: “Charlie, I have finished His Lordship’s waakye. Tell him the cat ate it.” Following this intelligence, investigators search the clerk’s drawer and discover:
- one empty takeaway pack;
- two boiled-egg shells;
- shito stains;
- a spoon; and
- Exhibit A—the unmistakable remains of gari.
Dwumoh, Counsel for the accused rises dramatically: “My Lady, this entire prosecution is the fruit of a poisonous tree!”
Her ladyship, Abena Buenz, looks at the empty waakye container. Then at counsel. Then at the accused. Then again at the empty container. This is the precise moment when constitutional principle must triumph over judicial emotion.
The judge cannot simply say: “Objection overruled. Nobody steals my colleague’s waakye and invokes Article 18.” The Constitution protects even people suspected of stealing judicial breakfast. Indeed, constitutional rights matter most when respecting them is inconvenient.
21. Conclusion: Can a Poisonous Mango Tree Nevertheless Bear Good mangoes in Ghana?
The answer under Ghanaian law is more interesting than either an unqualified yes or no. The American doctrine of the fruit of the poisonous tree provides a powerful metaphor for understanding evidence derived from illegality. But Ghana has not adopted a rigid rule that every piece of evidence connected to unlawful conduct must automatically be excluded.
The starting point under NRCD 323 remains the broad admissibility of relevant evidence subject to statutory and judicial limitations. The transformative authority is Raphael Cubagee v Michael Yeboah Asare & Others. The Supreme Court recognised that evidence obtained through violation of constitutionally guaranteed rights raises concerns transcending ordinary relevance and adopted a discretionary exclusionary approach.
Consequently, the Ghanaian judge must balance competing considerations: the nature of the right violated, the seriousness and deliberateness of the violation, the importance of the evidence, fairness to the parties, the public interest and, above all, the integrity and reputation of the administration of justice.
The crucial distinction is therefore between saying: “The tree is poisonous; therefore every fruit must automatically be destroyed.” and saying: “The tree is poisonous. Before anybody eats the fruit, however, the court must find out where it came from, how poisonous the tree really was, whether the fruit actually grew from that tree, whether another healthy tree produced the same fruit, and what serving it at the judicial table would do to the administration of justice.”
That latter approach more accurately captures contemporary Ghanaian law. Thus, in Ghana, the doctrine might better be restated: The Fruit of the Poisonous Tree Is Not Automatically Poisonous—but the Court Must Be Very Careful Before Taking a Bite. And if the disputed fruit happens to be another judge’s missing pack of waakye, the presiding judge would be well advised to recuse herself.
Selected Authorities
Constitution of the Republic of Ghana, 1992
- Article 12
- Article 15
- Article 18(2)
- Article 19
Evidence Act, 1975 (NRCD 323)
- Sections 51 and 52
- Relevant statutory provisions governing confessions
Ghana
- Raphael Cubagee v Michael Yeboah Asare & Others [2018] GHASC 14, Supreme Court, 28 February 2018.
- Tormekpey v Ahiable [1975] 2 GLR 432.
Comparative Authorities
- R v Leatham (1861) 8 Cox CC 498.
- Silverthorne Lumber Co v United States 251 US 385 (1920).
- Nardone v United States 308 US 338 (1939).
- R v Sang [1980] AC 402.