Stephen Lawrence murder: ex-detective cleared of corruption

John Davidson pictured in 2006. Photograph: BBC/PA/PAStephen Lawrence’s best friend has said a multimillion-pound investigation into fears the murdered schoolboy’s killers were shielded by corruption has collapsed.The investigation’s prime suspect, a former detective called John Davidson, has been told no evidence of corruption has been found against him.It follows an investigation lasting nearly four years by the National Crime Agency into longstanding corruption claims in the