A man already serving a sentence for sexual assault was brought from Midlands Prison to deal with harassment charges, dating back to the period from 2010 to 2014.
Judge John Brennan heard that the 58-year-old sent a series of worrying messages over the internet to a 16-year-old girl.
The judge felt that though this was a serious case, the messages were not sexually explicit.
They had resulted in the teenager feeling sick inside, leaving her with issues of trust and self-confidence.
Her tormentor lived in the same area and some of the messages contained information leading her to believe that she was being watched.
He appeared to know when she was on holidays and when she was in a local pub.
Defending counsel suggested that her client had led a very isolated life and never had any meaningful employment.
She assured the judge that the defendant was dealing with his problems while in prison and that he intended to change address once released.
The judge recorded a four month prison sentence, to be served concurrent with the existing term which was imposed in the Circuit Court for offences which occurred more than a decade ago involving a different injured party.
The defendant is due for release from jail in summer of 2019.