A police officer will not face prosecution over the death of Rashan Charles.
The 20-year-old died shortly after being detained on the floor of a shop in Dalston, east London.
On Sunday the Crown Prosecution Service concluded that it did not have enough evidence to proceed with a case.
Mr Charles's arrest in July last year was caught on CCTV in which he appeared to struggle with an officer and a member of the public.
An investigation found that attempts were made to remove an object from Mr Charles's mouth - which was later established to be a mixture of caffeine and paracetamol.
He died shortly after in hospital.
Mr Charles's death resulted in violent street protests with threats made against officers.
The CPS had been considering a common assault charge against the officer after a referral from the Independent Office for Police Conduct.
A CPS spokeswoman said: "Following the death of Rashan Charles in July 2017, the Independent Office for Police Conduct referred a file of evidence in relation to one Metropolitan Police officer for a possible charge of common assault.
"The CPS has considered the matter and decided the evidential test for a prosecution for common assault is not met. We will therefore not be taking any further action regarding this offence."
An inquest into Mr Charles's death is expected to be held in front of a jury on June 4.