Anonymous threats were made against prison officers who accused colleagues of plotting an attack on a sex offender at a top-security prison near York, it has been claimed.

On Saturday, the Evening Press exclusively revealed that three prison officers had been suspended and police were called in to investigate the conspiracy allegations at Full Sutton Prison earlier this year.

In December last year a sex offender was rushed to hospital with a fractured skull after he was badly beaten by other inmates.

Staff and inmates were interviewed by Humberside Police between February and May, but last month the Crown Prosecution Service returned the case file to police and said there was not enough evidence to proceed.

Now a source, close to an officer who told prison bosses he suspected colleagues of conspiring in the attack, has said a string of threats were made during the police probe.

The source claims:

An anonymous letter was sent to the officer which read: "You are scum. You are not one of the boys any more".

A package containing grass cuttings was sent to him in the prison's internal mail.

Silent late-night phone calls were made to his home.

A mirror was left smashed on the doorstep of another officer's home, near the prison, and an anonymous note stuffed through the door which read: "Seven years' bad luck and you're going to suffer every single one of them".

The source said the officer had reported the alleged incidents to police through a governor at the jail.

It added that the officer had told prison bosses of his suspicions about the attack because a colleague had told him what was going to happened the day before it did.

The source said: "He has suffered lots of grief because he decided to stand up for what he thought was right.

"He broke an unwritten golden rule that you don't report on other officers.

"It was a can of worms and he took the lid off it and he has suffered for it ever since."

A Prison Service spokeswoman said governor David Roberts maintained there was no evidence of tension among staff at the jail.

She said no allegations of harassment, bullying or victimisation had been made, but if any were they would be investigated.

Humberside Police were unable to confirm whether the alleged anonymous threats had been reported to them.

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