Murder accused told doctors that release of abuser Michael Ferry caused him to 'spiral'

A 39-year-old man from Carrickcoyle in County Donegal's Gaeltacht has been found not guilty of murder by reason of insanity following a jury verdict at the Central Criminal Court in March 2026. Derek Mulligan was charged with the fatal assault of his grandfather, Derek Burns, aged 78, at their family home on 19 December 2023. The incident involved the use of a granite stone and cement block. Medical evidence presented during the trial established that Mulligan was suffering from paranoid schizophrenia at the time of the killing. Two consultant psychiatrists, representing both the prosecution and defence, converged in their assessment that he met the legal criteria for the special verdict. The experts testified that Mulligan had experienced auditory hallucinations instructing him to kill his grandfather and had ceased taking prescribed antipsychotic medication approximately three months before the incident. The court heard evidence of significant trauma in Mulligan's background. He had suffered childhood sexual abuse, and psychiatric assessments indicated that the release from prison of his abuser in 2021 had triggered a marked deterioration in his mental health, causing what medical professionals described as a considerable spiral in his condition. Additional losses, including the death of his father when Mulligan was 16, compounded his vulnerability to mental illness. Beyond the murder charge, Mulligan faced four further counts arising from 17 December 2023, including criminal damage, threatening behaviour, and two counts of assault on other individuals. The jury returned majority verdicts on all counts on the basis of insanity. Following the verdict, Justice Eileen Creedon committed him to the Central Mental Hospital in Portrane, where ongoing psychiatric assessment and inpatient care would continue.