The inquest is hearing from the Detective Inspector from the Standards Department at the Met Police who says there is no evidence to back any of the claims.
The Professional Standards Detective tells the inquest jury that when the anonymous letter was sent for forensic examination, DNA was found on envelope. Billion to one chance DNA belonged to the unnamed defendant, jury is told.
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The mother of a boy who is in a critical condition in hospital after he was stabbed in a street attack has issued an emotional appeal.
Police said seven men were arrested during West Ham's EFL Cup fourth round win over Chelsea at the former Olympic Stadium.
Damon Smith, 19, has been charged with making or possessing an explosive substance with intent to endanger life.