Northern Ireland police ombudsman Michael Maguire today reopened the investigation into the murder of IRA informant Denis Donaldson.
The senior Sinn Fein official was shot dead in a remote cottage in Co Donegal in April 2006, where he had been living since his exposure as an MI5 agent in 2005.
His family claims the police were involed, but former ombudsman Al Hutchinson closed the inquiry three years ago and cleared officers.
Family solicitor Ciaran Shiels said Mr Donaldson's MI5 handler wasn't interviewed and investigators were unaware of his journal, which has now been handed over.
Mr Donaldson's family said they were "deeply concerned" about the case's handling, and said the "acid test" would be whether police officers fully co-operated with the probe.
"We are determined to hold these individuals to account."
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