A man is to be charged with the murder of former Sinn Féin member and British agent Denis Donaldson.

A senior garda decision to categorise a domestic disturbance complaint against a garda whistleblower as an incident causing serious harm or death was later questioned by the Garda Ombudsman.

An important witness has not been interviewed by gardaí investigating the murder of Sinn Féin spy Denis Donaldson, an inquest has heard.