Yesterday, they were told that Julian Cuddihy, from Churchtown in Carndonagh suffers from paranoid schizophrenia.
James Cuddidy Jnr. found his parents’ bodies in the family home on the morning of October 23rd 2014.
It later emerged that his 43-year-old brother Julian had killed them with an axe the day before.
Yesterday, the court heard from two forensic psychiatrists who both concluded he was having a psychotic episode at the time.
He believed the IRA was trying to recruit him and was hearing voices telling him to enter a parallel universe.
He was convinced his mother Kathleen wanted him to kill both her and his father James Snr. so they could go to heaven.
Afterwards, the court heard he spent the night in a nearby field waiting for a spaceship to take him to the Matrix.
Julian has pleaded not guilty to murder by reason of insanity.
The jury will be sent out later today to decide if he fits the criteria for the special verdict.
