The Daily Mail's long-running libel campaign against the accused - in contempt of court - would have prejudiced the jury too, even though the "evidence" consisted of two hairs, a few fibres and a tiny blood spot on clothing that the police admitted contaminating, and despite the fact that there were no reliable witnesses to the murder.
By the time of the trial the MacPherson Report had suggested that, had it not been for police "racism", the culprits would have been sent down years ago. So it recommended the abolition of the ancient double jeopardy rule - which had prevented suspects from being tried twice - in order to justify a retrial. Prior to this abolition, a suspect could only be retried if there was substantial new evidence against him.
Whether these men killed Lawrence or whether Brooks did - Lawrence's family hated him for dragging their son into the local underworld - is irrelevant in apartheid Britain. These days you are innocent until proven white.