Key Legal Defenses in Criminal Law: Tanzania

For a person to be held criminally liable, they must act with free will, combined with the necessary malicious intent (mens rea). That is, the crime must contain two essential elements—actus reus (the guilty act) and mens rea (the guilty mind). However, under certain circumstances, individuals who commit crimes may be deemed not criminally liable for the offense. Below, we discuss general defenses that may be raised in appropriate criminal trials.

Ignorance of the Law 

The principle governing ignorance of the law is provided under section 8 of the Penal Code (Cap 16 R.E 2022). According to this provision, ignorance of the law does not constitute a defense in criminal trials. An individual's lack of knowledge of the law cannot excuse any act or omission that would otherwise amount to an offense. This rule is based on the presumption that everyone is expected to know the law, stemming from the Latin maxim "ignorantia juris non excusat", which means ignorance of the law is no excuse, in contrast to "ignorantia facti excusat", which means ignorance of fact may be a valid excuse.

The rationale behind this ruFle is practical, as it would be challenging to prove in every case that an accused person was aware of the specific law they violated. For instance, in an old English case, a sailor was convicted for violating an Act of Parliament that had been enacted while he was at sea, with the offense occurring before he could learn of the new law. This is illustrated in R. v. Bailey (1800) R & R.1. In Tanzania, the case of Maulid v. R. (1970) H.C.D No. 346 provides another example. The appellant was convicted for failing to prepare and maintain records of oral contracts for his employees, failing to insure employees, and failing to pay the minimum wage. Evidence showed that he paid his barmaid Tshs. 60 while the required wage was Tshs. 170 per month. The appellant claimed ignorance of the legal requirement to insure his employees and to formalize their contracts. This plea was rejected on the basis that ignorance of the law does not afford an excuse.

The judge added that, “Even if we accept the appellant's claim that he was unaware of the law, I believe these statutory offenses are absolute and do not require mens rea. Nonetheless, it is crucial to note that there is no presumption that everyone knows the law. In fact, I doubt whether this presumption applies even to those responsible for enforcing the law. The principle remains that ignorance of the law is not a defense, which is distinct from presuming that everyone knows the law.” See Musa & Others v. R. [1970] E.A. 42. 

Bonafide Claim of Right 

This defense is provided under section 9 of the Penal Code and is available to an accused person under the following conditions:

The claim must relate to property: 

The defense may only be invoked if the offense in question concerns property. For instance, if person A destroys person B's car because B had beaten A’s child, A can be charged with malicious damage to property. In this case, the defense of claim of right would be available to A, as the claim concerns property. This defense is not limited to theft-related offenses alone; section 9 explicitly states that the offense must relate to property. This principle was confirmed in the case of Yusuph Hussein v. R. (1969) H.C.D No. 36, where it was held that the claim of right defense applies not only to theft but also to other property-related offenses, such as malicious damage. However, if A had assaulted B’s child because B injured A’s cow, this defense would not be available, as the claim would concern a person, not property.

The claim of right must be made in good faith (bona fide):

The person appropriating the property must do so in good faith, honestly, and without fraud. It is essential to consider the intent of the individual taking the property. If their intention was not fraudulent as per section 258 of the Penal Code., their claim is considered bona fide. A classic example of this is the case of Mohamed Hassan v. R. (1969) H.C.D No. 71, where the appellant, a house servant, admitted to taking clothes from his employer’s room after being dismissed without receiving three months' wages. He took the clothes to compensate for the unpaid wages. The High Court allowed the appeal, ruling that if his story were true, it would constitute a defense of claim of right, as the appellant may have genuinely believed he was entitled to the property.

Similarly, in Lenderito Laidosoli v. R. (1970) H.C.D No. 169, the appellant took two suitcases and a bed sheet from a tenant who had left without paying rent. The court found that the appellant acted under a claim of right because he believed he was entitled to the items in lieu of the unpaid rent.

The claim must be made with an honest belief in a legal right: 

The defense does not require the accused to have an actual legal right; it is sufficient if they honestly believe they had such a right. In Salum Mbegu v. R. [1981] T.L.R. 38, the court ruled that it is not necessary for the right claimed to be legally recognized, but it is enough if the accused honestly believed they had such a right in relation to the property. In Oyat v. R. [1967] E.A. 827, the accused seized five oxen that had damaged his crops and later sold one ox to recover compensation. The court found that he had a valid claim of right.

Another example is Salum Ibrahim v. R. (1971) H.C.D No. 481, where the appellant, after divorcing his wife, took household goods that he had bought during the marriage. When he learned that she had an affair, he assaulted her and removed several items. The High Court allowed the appeal on the charge of robbery with violence concerning the claim of right. It held that, while his claim might have been legally unfounded, it was honestly held and could serve as a defense to the charge of theft, though the assault charge was upheld.

Mistake of Fact

Mistake of fact is a defense provided under section 11 of the Penal Code. This defense applies to all mistakes of fact but not to mistakes of law. For instance, if A and B are caught hunting in a restricted area, and A claims he was unaware that hunting there is illegal, while B argues he did not know they had crossed into the restricted area, A would be pleading ignorance of law, and B would be claiming mistake of fact. As a result, A would not be excused, whereas B may be excused. According to section 11 PC., the defense of mistake of fact must be based on an honest, reasonable, and mistaken belief.

For the defense to apply, the mistake must be such that if the accused’s belief about the situation had been correct, they would not have been guilty of the offense. While some mistakes of fact negate mens rea (the guilty mind), others do not, meaning the accused may still be convicted. For example, if A intended to kill his enemy B but mistakenly killed C, A would still be guilty of murder because, had the circumstances been as he believed, A would still have been convicted of the offense.

Mistake of fact must be both honest and reasonable, as established in the case of R. v. Sultan Maginga (1969) H.C.D. No. 33. In this case, the accused, while guarding his shamba from wild pigs, saw a movement in the grass at night. After calling out and receiving no response, he threw a spear at a shadow, fatally wounding the deceased. The court found that the accused did not know he was throwing a spear at a person, and the charge of murder could not be sustained. The judge also declined to find the accused guilty of manslaughter, as there was insufficient evidence of recklessness.

In contrast, the case of R. v. Selemani Hassani (1969) H.C.D. No. 250 demonstrates when a mistake of fact may lead to a conviction. The accused, while chasing wild pigs, fired a shotgun at a shadow in a maize field, believing it to be a pig, but the shadow was actually his brother-in-law. The court found the accused guilty of manslaughter, ruling that his actions amounted to extreme recklessness, as it was reasonable to expect that the deceased might have been in the field.

The reasonableness of a mistake is judged objectively, not subjectively. Thus, even if a mistake is honestly held, if it is found to be unreasonable, it will not provide a defense in a criminal trial. In R. v. Kajuna (1945) 12 E.A.C.A. 104, the appellant killed his father, believing in error that his father was causing the death of the appellant's child through supernatural means. The court ruled that a belief in supernatural powers, regardless of its honesty, cannot be considered reasonable in law.

Section 11 P.C. contains a proviso that allows for the exclusion of this defense by express or implied provisions of law, which would create an offense of strict liability.

Insanity

The defense of insanity is governed by section 13 of the Penal Code (PC), which was influenced by the principles laid down in the famous case of R. v. M'Naghten (1843). In this case, Daniel M'Naghten, who was suffering from a mental illness, mistakenly killed Edward Drummond while intending to assassinate Sir Robert Peel. His acquittal due to insanity led to public outcry, and as a result, the M'Naghten Rules were established, forming the foundation of the insanity defense in criminal law.

According to section 13 P.C, an individual is not criminally liable for an act or omission if, at the time of committing the act, they were suffering from a mental illness that rendered them incapable of understanding the nature of the act or of knowing that the act was wrong. The law presumes that all persons are sane, as stipulated in section 12 TPC, until proven otherwise. To successfully raise the defense of insanity, it must be demonstrated that the accused was affected by a disease of the mind to the extent that they could not comprehend their actions or recognize their wrongfulness.

This principle was applied in the case of R. v. Tomson Msumali (1969), where the accused, an epileptic, killed his father during an episode where he mistakenly believed he was defending his father from an assailant. The court found that Msumali was not criminally responsible due to his inability to understand his actions at the time, caused by his mental illness. Similarly, in Nyinge Suwatu v. R (1959), the appellant killed a police inspector under the delusion that the inspector was plotting his death. Although he knew what he was doing, he did not comprehend that it was wrong.

In contrast, if the accused understands their actions but still commits the act due to a delusion, the defense may not be fully available. For instance, in R. v. Said Mwamwindi (1972), the court held that the mental disease must directly affect the specific act in question. It is not enough to have a history of mental illness; the illness must impair the individual’s understanding at the time of the offense.

The defense of insanity also includes cases of insane delusions. A person acting under a delusion is judged based on whether the delusion, if true, would justify their actions. If the delusion led the individual to believe they were acting in self-defense, they may be acquitted. However, if the delusion caused them to act out of revenge or malice, they remain liable for their actions, as seen in R. v. Kibiegon Arap Bargutwa (1939). In this case, the appellant attacked and killed his father under the delusion that his father had attempted an indecent assault on him. The court convicted him of manslaughter, acknowledging the delusion but holding him responsible.

The insanity defense is treated as a partial defense under Tanzania law, meaning that even if successful, the accused is detained as a "criminal lunatic" rather than being fully acquitted. The court, aided by assessors, decides the issue of insanity as a matter of fact, and while medical experts' opinions are highly regarded, they are not binding on the court. This was emphasized in the case of *Hilda Abel v. R [1993] T.L.R 246, where the court acknowledged the appellant's mental disturbance but ultimately found her sane under section 13 TPC.

Insanity, therefore, operates as a limited defense that can reduce criminal responsibility, but it does not always absolve the accused of legal consequences.

Intoxication

Intoxication generally does not provide a defense to criminal charges. However, under section 14(2) of the Penal Code, intoxication may be considered a defense in specific situations. These include cases where: (i) the accused, at the time of the offense, did not understand what they were doing; (ii) the intoxication was caused by another person either negligently or maliciously; and (iii) the accused was temporarily insane due to intoxication. If the intoxication defense is accepted, the accused is discharged but not acquitted, allowing the prosecution to reopen the case if new evidence arises. 

In D.P.P v. Beard [1920] A.C. 479, the court ruled against a defendant who claimed intoxication as a defense for rape and murder. His actions, like covering the victim's mouth to prevent her from screaming, demonstrated that he was aware of his violent conduct. In contrast, cases where intoxication leads to insanity, like in R. v. Rotief (1941) E.A.C.A 71, may provide a valid defense if the intoxication-induced insanity prevents the accused from understanding the nature of their actions. The court treats intoxication-induced insanity similarly to any other form of insanity.

Additionally, intoxication is relevant in determining whether the accused formed the necessary intent for a crime. In Kinuthia Kamau v. R. (1950) 17 E.A.C.A 137, excessive drunkenness led the court to substitute a murder conviction for manslaughter because the accused was unable to form the intent to kill. Similarly, in R. v. Nyode Wopera (1948) 15 E.A.C.A 145, despite intoxication, the accused was found guilty of murder because the court determined he had the intent to kill or cause grievous bodily harm.

In the case of R. v. Michael Chibing'ati [1983] T.L.R. 441, the accused, after consuming alcohol, attacked his brothers, leading to the death of one. The court accepted that the accused was drunk but ruled that his intoxication did not reach the level of legal insanity. The court also considered self-defense based on a mistaken belief due to intoxication, but the provocation defense was not available as the accused initiated the violence against his mother.

Immaturity

Immaturity, in the context of criminal law, refers to an age below which a person is deemed incapable of committing a criminal offense. Under section 15 of the Penal Code, a child under the age of ten years is conclusively presumed incapable of committing a crime, making this an irrebuttable presumption. However, for children between the ages of ten and twelve, there is a rebuttable presumption of incapacity. The prosecution must prove that the child understood the wrongfulness of their actions at the time of committing the offense. In sexual offenses, however, the law takes a stricter stance, deeming any child under the age of twelve incapable of having carnal knowledge, an irrebuttable presumption.

An illustrative case is R. v. F. 2 N.R.L.R.185, where a ten-year-old boy stole a wristwatch and attempted to sell it, supported by deceitful actions such as forging a note. The court found that the boy had the capacity to understand the wrongfulness of his actions, thereby rebutting the presumption of immaturity, and he was convicted of theft.

Compulsion and Coercion

Compulsion or coercion, as defined under section 17 of the Penal Code, refers to the act of forcing someone to commit a crime against their will by the use of or threat of immediate violence. To successfully raise this defense, the accused must demonstrate several elements. First, it must be shown that the accused committed the offense alongside another person or persons, though they do not need to be jointly charged, as held in Josiah v. R. [1972] E.A 157. Secondly, the accused must prove that they were threatened with immediate death or serious injury if they refused to commit the crime. The threat must be directed at the accused, not another person or property, and threats of future harm do not qualify for this defense. Lastly, the accused must show that the threats persisted throughout the commission of the offense, as reiterated in Josiah v. R.

Judicial Privilege

Section 16 of the Penal Code grants protection to judges, justices of the peace, and other judicial officers from criminal prosecution for acts or omissions done in good faith while exercising their judicial functions. This protection ensures that judicial officers are not prosecuted for their judicial decisions, as long as these decisions are made bona fide. The privilege applies strictly within the scope of their judicial duties, as shown in cases like Mzee Selemani v. R. (1968) H.C.D No. 364, where an executive officer was convicted for overstepping his authority.

Compulsion by Husband

Under section 29 of the Penal Code, a married woman may claim compulsion by her husband as a defense for offenses committed under his coercion, as long as the offense is not murder or treason, was committed in his presence, and she acted under his coercion.

Defense of Person or Property

Section 18 of the Penal Code outlines the legal framework for the defense of person or property. A person may use reasonable force to protect themselves or their property, but any excessive force can result in criminal liability. The principle of reasonableness is key, as established in Selemani Ussi v. R. [1963] E.A 442, where the court held that a person has no duty to retreat if a violent felony is being attempted against them. However, excessive force may lead to a conviction of manslaughter instead of murder.

In R. v. Nyakabo (1970) H.C.D No. 344, the accused was acquitted of murder after defending herself against sexual assault from her father-in-law. The court ruled that she acted reasonably in defending her life and chastity, as the deceased attempted to throttle her during the assault. Other cases, such as Daudi Sabaya v. R. [1995] T.L.R 148 and Salum Abdallah Kihonyile v. R. [1995] T.L.R 349, illustrate the limits of self-defense. In Sabaya, the appellant used excessive force and was found guilty of manslaughter. In Kihonyile, the court rejected the defense of self-defense when the accused speared the deceased from behind, as the deceased was no longer a threat.

Similarly, in Claylaway v. R. [1992] T.L.R 72, the court dismissed the plea of self-defense when the accused killed someone on suspicion of being poisoned. In Moses Mungasiani Laizer @ Chichi v. R. [1994] T.L.R 222, the court acknowledged that the defense of self-defense could apply even to someone who started a fight, depending on the circumstances, though the offense would be reduced to manslaughter.

The defense of others is also recognized, as demonstrated in Ilapala Ibrahim v. R. 20 E.A.C.A 300, where killing in defense of another person was deemed justifiable if the accused acted reasonably and without vindictiveness.

Defense of Property

The defense of property, like self-defense, operates under the principle of reasonableness. It allows individuals to protect their property using reasonable force, especially in situations where the trespasser refuses to leave after being asked. The law generally permits the use of force only after non-violent means, such as a request to leave, have been attempted. If the trespasser fights back, the defender can apply self-defense principles. The owner of the house, for instance, is not obligated to retreat, especially in cases where trespassers forcibly enter. However, the use of lethal force is limited and is generally only justified when the defender’s life is also threatened, as established in Mohamed Ally v. R. (1969) H.C.D No. 54, where the court ruled against the use of firearms in defense of property unless life is endangered.

A similar stance was taken in R. v. Mohamed Ndewe and Others (1970) H.C.D No. 211, where the court noted that property alone does not justify killing a thief. However, if the thief uses a weapon and poses a serious threat to the defender’s life, the use of lethal force may be permissible. The court evaluates the circumstances of each case to determine whether the force used was justifiable, potentially reducing the charge to manslaughter if the force was excessive but not grossly unreasonable.

Necessity

The defense of necessity, although not codified in the Penal Code, is recognized as a common law defense. It is invoked when a person commits an offense to prevent greater harm, such as breaking a traffic law to take an injured person to the hospital. However, in serious cases like homicide, necessity is interpreted strictly. The value preserved must be greater than the harm caused, but in life-for-life situations, the law treats both lives as equally valuable, making necessity an inapplicable defense. This principle was firmly established in R. v. Dudley & Stephens (1884) 14 QB 273, where the court rejected the defense of necessity when two shipwreck survivors killed and ate a cabin boy to survive.

In less severe cases, such as R. v. Abbas Mohamed (1969) H.C.D No. 113, the defense of necessity was applied when the accused, without the proper license, drove to pick up his sick uncle from the airport. The court accepted that the accused was facing an emergency and acted reasonably, emphasizing that economic necessity or personal convenience, however, is not a valid defense to criminal charges, as the law does not allow individuals to take it into their own hands.