Police have sent a written apology to the family of ex-footballer Dalian Atkinson, six months after an officer who Tasered him and kicked him in the head was jailed for manslaughter.
West Mercia's Chief Constable Pippa Mills said she was "deeply sorry".
"A police uniform does not grant officers immunity to behave unlawfully or to abuse their powers," she wrote.
PC Benjamin Monk's conviction was the first for a death in custody in 30 years.
The family of Mr Atkinson, a former Premier League star with Aston Villa, had said the case showed the need for change in the way black people were treated by police and the criminal justice system, in the wake of the Black Lives Matter movement.