Courts / Dublin / Report

Man fatally stabbed in Derek Boyd's home had admitted assaulting girlfriend, trial hears

Date
2026-07-15

Stage
Sentence

Primary locality
Dublin

County
Dublin

Summary

Derek Boyd, 31, pleaded not guilty to the murder of Mark Carroll, 34, at a Finglas home on June 9, 2024, and to threatening and assaulting Megan Rock. His partner, Chantelle Harcourt, 34, pleaded not guilty to impeding the prosecution of an arrestable offence. The Central Criminal Court trial heard that Boyd was serving a suspended sentence for the 2022 manslaughter of his sister, Sandra Boyd, and unlawful possession of a firearm. He received a four-year sentence for manslaughter, with the final two years suspended, and a concurrent five-year sentence for firearm offences, with the final three years suspended. The court noted he was under active supervision when Carroll died. The prosecution alleges Boyd stabbed Carroll with intent to kill or cause serious harm. Boyd claimed self-defence, stating Carroll lunged at him. Evidence detailed Carroll's history, including a guilty plea to assaulting Rock in Ashbourne, Co Meath, where she was found bruised and shaking, and a pending charge for assaulting a man in Dublin 7 in 2022. The trial continues before Ms Justice Melanie Greally.

Who, what, where, when and why

What: Report matter: Man fatally stabbed in Derek Boyd's home had admitted assaulting girlfriend, trial hears. Charges or matters: assault causing harm to his girlfriend Megan Rock in her home, where gardai noted on arrival that she was bruised, bloody-faced and visibly shaking; one count of the manslaughter of his sister Sandra Boyd on October 7, 2022; two offences because he had not been sentenced before his death; assault causing harm to a 36-year old man in 2022, which allegedly occurred on the Phibsborough Road in Dublin 7; assault causing harm to Megan Rock at her home in Ashbourne, Co Meath as well as another offence. Procedural stage: sentence

When:

August 2025 Hearing Or Sentence
October 7, 2022 Incident
March 21, 2022 Other
June 9, 2024 Other
2026-07-15 Publication

Why: However, he agreed there was a "curious quirk" in the garda Pulse' system, in that it did not record that the deceased had pleaded guilty to two offences because he had not been sentenced before his death. CNI source report

Case subjects

Chantelle Harcourt

Defendant

Plea: Not guilty

Derek Boyd

Defendant

Charges: assault causing harm to his girlfriend Megan Rock in her home, where gardai noted on arrival that she was bruised, bloody-faced and visibly shaking; one count of the manslaughter of his sister Sandra Boyd on October 7, 2022; two offences because he had not been sentenced before his death; assault causing harm to a 36-year old man in 2022, which allegedly occurred on the Phibsborough Road in Dublin 7; assault causing harm to Megan Rock at her home in Ashbourne, Co Meath as well as another offence (Admitted)

Plea: Guilty

Outcome: Derek Boyd was serving a suspended sentence for the manslaughter of his sister by "a reckless or negligent discharge of a gun" when he fatally stabbed a man at his north Dublin home, a Central Criminal Court jury has heard. The detective said Mr Boyd was given a four-year sentence with the final two years suspended for the manslaughter and a concurrent five year sentence with the final three years suspended for the firearm and ammunition offences.

Mark Carroll

Defendant

Plea: Guilty

Outcome: The witness agreed that Mr Boyd was still under active supervision in terms of the suspended sentence at the time of Mr Carroll's death.