On January 6th, 1967, less than 2 days after the murder,
businessmen in Newcastle were receiving threats to their
businesses and personal safety.
Below is just one example of the threats being made:

This statement was suppressed by the police and was not given to the Defence at the trial in 1967.
It only came to light in 1972.
Who was making those threats?
Why was this not followed up by police?
Further investigation of this and many other threats may have led to the capture and conviction of the real killers of Angus Sibbett.