17 May 1978
When Steve Biko was found dead on a cold cement floor in a Pretoria prison, police claimed that he died of hunger strike. The following investigation failed to produce concrete evidence and was officially closed on 17 May 1978.It was only in 1985 that the real circumstances surrounding Biko’s death were officially revealed and the people involved brought to book, including the police officers that assaulted him and the two doctors who treated him just before his death.
References

SAHO Biko, Stephen Bantu, [online], Available at: www.sahistory.org.za [Accessed on 9 May 2013]|News 24, How Biko died, [online] Available at: www.news24.com [Accessed on 9 May 2013]