The IPCC said the three arrested were a 50-year-old sergeant who was arrested at work, a 29-year-old Pc arrested at an address in south London and a retired PC aged 48 who was arrested by appointment at a central London police station.
Sean Rigg died from a cardiac arrest at Brixton police station in August 2008 and the inquest jury found that police officers used "unsuitable" force after arresting the 40-year-old schizophrenic for attacking passers-by and police officers in Balham, south London.
More top news
National Audit Office figures show 2.7 million 'hospital bed days' are lost each year due to delayed transfers of care.
Parliamentary inquiry finds thousands of children could fall prey to sexual exploitation and gangs because of flawed warning systems.
David Cameron said the June 23 referendum is the most important vote young people will place in their lifetimes.