An independent review of police custody deaths in England and Wales has been announced by the home secretary.
The review, which will also cover serious non-fatal incidents, comes after a string of high-profile cases and allegations of wrongdoing.
Theresa May said she had been struck by the “pain and suffering” of families amid seeming evasiveness and obstruction.
The review will examine “procedures and processes” in such situations.
The plan to review how deaths in custody occur – and how they are investigated – comes after the police complaints watchdog was attacked for inadequately getting to the bottom of a number of fatalities.
In 2013, a review found that the Independent Police Complaints Commission had committed a series of blunders in its investigation of the 2008 death of Sean Rigg, a mentally ill man detained at Brixton police station.
The original investigation concluded police had acted reasonably and proportionately – a finding rejected by a jury at Rigg’s subsequent inquest.
Rigg’s sister Marcia Rigg-Samuel told the BBC the review had been “a long time coming”.
She added: “What I want, and I speak for myself and on behalf of other families, is that this review is effective and brings real change on the issue of deaths in custody, and how families feel and how we are treated, and that there’s proper accountability.”
Rigg-Samuel also said families should be “at the core of the review”, to give them confidence that changes will be made.
“When you lose a loved one in state custody, it’s bad enough having to deal with the death. What’s extraordinary is the systematic failures, and the answers that we cannot get, from the state officials. It’s devastating for any family.”