The court unanimously affirmed that the doctrine of common purpose was compatible with the Constitution, upholding two murder convictions on that basis.

Earlier that day, a group of residents, described variously as a vigilante or as protestors, had driven in a motorcade through the township; they allegedly attacked the houses of several individuals whom they suspected of drug dealing, including Grant Cronje.

The defendants contended that the doctrine is inconsistent with the constitutional rights to dignity, freedom of the person, and a fair trial.

Therefore, they held that the Supreme Court of Appeal had been obliged, in terms of section 39(2) of the Constitution, to develop the doctrine of common purpose in order to bring it into compliance with the Bill of Rights.

However, he had not disclosed his alibi upon his arrest – including during a brief conversation with a police sergeant – nor at any point during the two years in which he was awaiting trial.

Both lower courts rejected Thebus's alibi, preferring the evidence of the witness who placed him at the scene of the shooting in Ocean View.

After discussing the proper application of section 39(2) of the Constitution and the circumstances in which it compels a court to develop or adapt the common law, Moseneke rejected the defendants' rights-based arguments.

He held that the doctrine of common purpose, as applied in the present case, passes constitutional muster and therefore does not trigger any judicial obligation under section 39(2).

However, each also agreed that, the constitutional question notwithstanding, Thebus's guilt had been proved beyond a reasonable doubt and the trial court had therefore been entitled to convict him.

However, his reasoning differed substantially from Moseneke's and was instead grounded in section 35(3) of the Constitution, which guarantees – in detailed terms – the right to a fair trial.

Goldstone and O'Regan also disagreed with Moseneke's finding that it is permissible to cross-examine an accused person about why they opted to exercise their right to silence.

Ngcobo held that the court need not reach the adverse inference question because, on the facts, Thebus's right to silence was not implicated.

To this inquiry, Thebus had not only failed to disclose his alibi; he had not exercised his right to silence, and instead had replied with an exculpatory statement to the effect that his family was in Hanover Park at the time of the crime.