A candlelit vigil will be held on Friday to remember Sean Rigg, the Tooting man who died in police custody.
Supporters will gather outside Brixton Police station, where the 40-year-old musician mysteriously died one year ago.
The Independent Police Complaints Commission (IPCC) is investigating the death, but the family has accused it of failing to conduct a fair inquiry.
Mr Rigg was arrested in Balham on August 21 last year when he suffered a breakdown brought on by his schizophrenia.
He was restrained and driven in a van to Brixton police station, but within two hours, the physically fit man was dead.
The family are still searching for answers and have joined the United Campaign Against Police Violence (UCAPV).
On Friday they will gather at Fairmount Road in Brixton Hill at 5.30pm before heading to the police station for the one year anniversary.
Samantha Rigg-David, his sister, said: “It’s nearly one year since Sean died, the time has gone so fast it is unbelievable.
“It has been a tough year to say the least and we continue to fight and campaign for answers.
“The family would like to thank everyone for their continued support and encouragement - without some of you we would never have made it this far, thank you again.”
Brixton Police and the IPCC have said they are committed to a thorough and impartial investigation.
For more information visit seanriggjusticeandchange.com