Mr Rigg died after being arrested in Brixton in August
Families of people who died in police custody have marched to Downing Street to ask the government to investigate.
There have been 182 deaths in police, prison or psychiatric custody over the past year, the United Families and Friends Campaign said.
They include Sean Rigg, 40, who died after being arrested in Brixton, south London, in August for alleged assault.
The Home Office said deaths in custody were "a very small percentage" of those who come into contact with police.
'Lack of will'
Campaigners marched from Trafalgar Square to ask Prime Minister Gordon Brown to set up a "genuinely independent" body to investigate deaths in police custody.
They also want officers allegedly responsible for deaths to face criminal charges, even if they have retired.
Campaign spokesman Ken Fero said the number of deaths in custody was "continually going up".
He said: "Every time there are new initiatives such as CCTV or something else which can prevent a death, it just escalates in other areas. So clearly there is a lack of will."
Recent deaths included Mr Rigg, arrested in Brixton on suspicion of assaulting a police officer and alleged public order offences on 21 August.
Mr Rigg fell ill and was seen by a doctor but he was pronounced dead in hospital shortly afterwards.
His sister Samantha Rigg-David said: "We are outraged that Sean's death has happened regardless of the countless recommendations made in previous cases."
A Home Office spokeswoman said there were 75 deaths involving people who came into contact with police over the past year - two of whom died in custody.
"Around 1.5 million people are arrested each year and nearly four million others are subject to street activity through stop and search or street penalties," the spokeswoman said.
"In that context, the number of deaths seems a very small percentage of all those who come into contact with the police. In reality, one death is one death too many."
She said the Home Office aimed to prevent deaths from occurring and "minimise harm to all persons coming into contact with the police".