James Redmond, aged 60, of Killinarden Estate, Tallaght, Dublin 24, is charged with murdering Mary Dargan and attempting to murder Karina Dargan at their home in Killinarden Estate on March 15, 2014.
Mr Redmond yesterday pleaded not guilty by reason of insanity to the charges at the Central Criminal Court.
Before the prosecution opened its case, Brendan Grehan, defending, made a number of admissions of fact on behalf of his client.
He said Mr Redmond pleaded not guilty by reason of insanity to the two charges and admitted he had killed Mary Dargan and attempted to kill Karina.
Ms Dargan told the court that, in March 2014, she was living with her own daughter in her mother’s house, which had been the family home for many years.
“I remember sitting at the kitchen table with my mum, my sister Jessie and her son,” said Ms Dargan. “We were having a giggle about Jessie’s upcoming wedding.
“I looked out at the corner of my eye and I saw him coming towards me.
“The blinds were open as it was a nice day out. I saw him walking in slow and calmly. He said: ‘Are you fucking laughing now?’ ”
The court heard Mr Redmond then shot her mother in the side of her face.
“I ran to get Gary and I heard a bang and I went down,” she said. “I just saw Gary’s feet running by me and I got up. My daughter was at the hall door. I knew my mother died immediately, I knew when I looked at her.”
She suffered a gunshot wound to the right hand side of her head, but escaped with tissue damage.
The court heard Ms Dargan knew the accused for the previous 28 years since they moved into the house next door.
The trial continues today.