The inquest into the death of Sean Rigg opened on Monday.
Sean, who suffered from schizophrenia, died on 21 August 2008 after being arrested and restrained by police in south London.
He was then taken to Brixton police station and held in a metal cage in the yard.
Police claim that the CCTV was not working either in the yard or the police van that carried Sean there.
He was pronounced dead at hospital later that night.
Sean’s sisters, Marcia and Samantha, have campaigned tirelessly to find the truth about their brother’s death.