A Bedford prisoner serving 25 years for attempted murder made death threats to his victim via mobile phone from the jail.
Farai Kambarami, aged 36, this week had a year added to his sentence for making threats to kill and using a prohibited item in jail.
He was also convicted of breaching a restraining order against his female victim, who he attempted to murder in Milton Keynes in August 2016.
Kambarami initially entered a not guilty plea at Aylesbury Crown Court. However changed his plea to guilty following the jury being sworn in this week.
The court heard that in July 2017 Kambarami used a mobile phone to call the victim of and threatened to kill her.
He was sentenced to one year imprisonment in relation to the threats to kill and the breach of the restraining order.
No additional sentence was imposed in relation to the possession of a mobile phone offence.
The sentence will run concurrently to the 25 year sentence he is currently serving.
Investigating officer Detective Sergeant Vince Higgins said after the case: “This offence was extremely distressing for the victim in the case as she had already gone through the original harrowing ordeal.”
He added: “ I am so glad that she again had the strength to pursue this complaint and we were able to convict Kambarani for these further offences.”