The Doctrine of Common Purpose

How the Law Holds Groups Accountable for Crime

Picture this: Twenty people throw stones at someone, and the victim dies. Without the doctrine of common purpose, each stone-thrower could plausibly avoid conviction by saying, “But Your Worship, you can’t prove my particular rock was the one that killed him.” It would be the criminal law equivalent of “it wasn’t me, it was everyone else”…a loophole so wide that even the most imaginative defence counsel would hesitate to use it.

This is precisely where the doctrine of common purpose plays a crucial role. It addresses the problem of group accountability in criminal law. Crime, like a dysfunctional group project, often involves multiple actors whose individual contributions are difficult to isolate. The doctrine ensures that where someone willingly joins a criminal enterprise, they cannot later rely on technicalities to avoid liability simply because the causal link between their act and the harm cannot be clearly established.

The doctrine of common purpose is a foundational principle in South African criminal law, intended to deal with evidentiary challenges in group crimes. It permits the conviction of individuals who participate in a joint criminal venture, even if their personal conduct cannot be identified as the direct cause of the unlawful outcome.

Under the ordinary principles of liability, criminal responsibility requires proof that an individual’s unlawful act caused the harm. In group settings, this becomes difficult. If twenty people jointly stone a person to death, applying the conditio sine qua non test¹ might yield the answer that no one individual caused the death, since the others’ actions would still have sufficed. The result is counterintuitive and would allow all twenty participants to escape liability. Without the doctrine, it would be possible to orchestrate attacks in large groups precisely to avoid individual culpability. The doctrine is designed to close this evidentiary gap and is rationally connected to a lawful aim.

The doctrine rests on the following key propositions:

If two or more individuals act in furtherance of a common criminal purpose, the conduct of each is imputed to the others.
In result crimes (such as murder), the consequence caused by one participant is attributed to the rest.
Deviant acts by one participant are not imputed to others unless the latter foresaw the possibility of such conduct and reconciled themselves to it.
A prior agreement is not required; common purpose can be inferred from conduct.
A person may be held liable based on active association with the commission of the crime, provided this occurs while the victim is still alive and before a mortal wound is inflicted.
In culpable homicide cases, causation may be imputed, but negligence cannot be.
The doctrine does not apply to autographic crimes (those that can only be committed using one’s own body).

The doctrine’s most frequent and controversial use is in murder cases. The central requirement is that each participant intended to kill and to assist others in doing so. Once this is shown, the act of the person who physically caused the death is imputed to others who actively associated with the common purpose. Causal connection is not required. The rationale is that by participating in a joint venture, a person forfeits the right to isolate their conduct from that of others. In essence: “your acts are my acts.”

Only conduct is imputed, not culpability. Each participant’s intention must be proven individually. The common purpose can arise spontaneously and does not require agreement on the exact mechanics of the offence.

In S v Safatsa,² the Appellate Division upheld murder convictions based on common purpose where a crowd attacked and killed the victim. The court held that active association with the group was sufficient and rejected the argument that individual causation had to be proven. The cornerstone of liability under this doctrine is active association, which includes more than prior agreement. While prior conspiracy simplifies the inference of shared purpose, it is not necessary. Presence at the scene is also not required if there is proof of prior agreement.

In S v Mgedezi,³ the Supreme Court of Appeal (SCA) set out five requirements for liability in the absence of a prior agreement:

Presence at the scene of the crime.
Awareness of the assault being carried out by others.
Intention to make common cause with the perpetrators.
Conduct manifesting shared purpose (mere presence or passive acquiescence is not enough).
Intention to kill.

This formulation is more stringent than liability based on prior agreement.

Intention need not be dolus directus; dolus eventualis suffices. If participants foresee that someone may be killed in the course of the crime and reconcile themselves to that outcome, they may be convicted of murder. For example, in a robbery where one accomplice is armed, the others may be liable if they foresaw the risk of death and accepted it. However, one person’s mens rea is not imputed to another. Culpability must be assessed individually.

The doctrine can also apply to culpable homicide to resolve causation difficulties. This was confirmed in S v Nkwenja⁴ and Magmoed v Janse van Rensburg,⁵ read with Safatsa. While causation may be attributed to the group, negligence cannot be. One cannot intend to be negligent, and each person’s negligence must be assessed on its own merits.

The doctrine does not apply to autographic crimes, which must be committed personally. For instance, under the now-abolished common-law crime of rape, a person who assisted (by holding down the victim) but did not engage in intercourse could not be a co-perpetrator, only an accomplice. Other examples include perjury, bigamy, and drunk driving.

Notably, liability may be avoided by effective withdrawal. The following elements are required:

A clear, unambiguous intention to withdraw.
A positive act of withdrawal (passivity is not enough).
Voluntariness (withdrawal prompted by police intervention is insufficient).
Withdrawal must occur before the execution phase of the crime begins.
The nature of the withdrawal depends on the role played. A leading figure may need to go further than a minor participant, such as warning the police or persuading co-perpetrators to abandon the plan.

Even if successful, withdrawal may not preclude liability for earlier conduct such as conspiracy or incitement. In S v Nzo,⁶ the accused successfully avoided murder liability by confessing the plot to the police in time.

A “joiner-in” is someone who assaults a victim after a mortal wound has already been inflicted by others but while the victim is still alive. If the second injury hastens death, the joiner-in may be guilty of murder through causation. If the assault occurs after death, no murder conviction is possible. Where there was no prior agreement, and no causation, the joiner-in may only be convicted of attempted murder. In S v Motaung,⁷ the court rejected the idea of ex post facto ratification of completed conduct.

In Thebus v S,⁸ the Constitutional Court upheld the validity of the doctrine of common purpose. The court found that it promotes a legitimate aim i.e., combating group criminality and avoiding a scenario in which only the person who inflicts the fatal blow is held accountable. The decision acknowledged concerns about the doctrine’s breadth but confirmed that it is consistent with constitutional principles when properly applied.

The doctrine of common purpose reflects the reality that criminal liability can arise in spontaneous group settings as much as in premeditated conspiracies. It balances the need for fairness with the imperative to avoid impunity in group crimes. It allows participants to be held accountable for their decision to take part in a joint enterprise, while also recognising the importance of personal culpability and the possibility of effective withdrawal. In essence, the doctrine sends a clear message: when you act with others to commit a serious crime, you share in the consequences. It closes a dangerous gap in the law while respecting individual liability, thereby fulfilling the core function of a sound legal principle.

Written by Theo Tembo