Mairead Moran died after being attacked while working at a Holland & Barrett shop in May 2014.
26-year-old Mairead Moran was originally from Kilmaganny in Co. Kilkenny, but had been living in Kilkenny city for several years.
At around 8.30 on the evening of May 8th 2014, she was stabbed several times while working at the Market Cross Shopping Centre.
Some passersby and workers from a nearby Supervalu ran to her aid, but she died from her injuries sometime later.
Today, Shane Smyth of McGuinness House, Express Lane, Kilkenny City pleaded not guilty to her murder by reason of insanity.
A jury was sworn in to hear his trial, which is due to begin hearing evidence tomorrow and is likely to take up to three days.