The man accused of being 'Stakeknife' - the British army's top spy in the IRA - has died.
Freddie Scappaticci always denied being a double agent.
He is said to have worked within the IRA's "nutting squad", interrogating suspected informers during The Troubles.
It has been claimed he was allowed to do this to gain the trust of the organisation's leadership and maintain his cover.
Retired British police chief Jon Boutcher has been investigating dozens of murders linked to 'Stakeknife' and the role played by his handlers and the security services - including Britain's MI5.
A report, known as Operation Kenova, was due to be published early this year but has been delayed.
Mr Boutcher said he was made aware of Scappaticci's death last week and his team were looking at the implications.
"We remain committed to providing families with the truth of what happened to their loved ones and continue to actively pursue criminal charges against several individuals," he said.
"We will publish an interim report on Kenova's findings this year".
He urged anyone who might now want to talk to investigators following Scappaticci's death to "contact us in confidence".
Scappaticci, who was from west Belfast, was in his late 70s and is understood to have already been buried.
He left Northern Ireland in 2003 after being widely named as 'Stakeknife'.
In 2018, Scappaticci appeared at a London court and admitted possessing extreme pornography.
Reporting by IRN
