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.
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Outbreaks of rain and strengthening winds will affect southernmost parts of England and Wales today.
An earlier debate on the issue was suspended as an 'expression of support' following the Westminster terror attack.
Five people were killed and dozens more were injured after a car and knife attack in the capital on Wednesday afternoon.