Iraq killings: Who's behind a series of murders?

On 6 July 2020, Hisham al-Hashimi, security adviser to Iraq's prime minister, was murdered outside his home in Baghdad.

As a fearless critic of the men of violence on both sides of Iraq's sectarian divide, Hisham was not short of enemies. But who killed him and why?

Ramita Navai and the BBC News Arabic team set out to investigate his death, the killings of several activists and the growing power of Shia militias in a year that saw the US reduce its military presence in Iraq.