Courts / Dublin / Report

Derek Boyd 'acted out of instinct' when he fatally stabbed 'trespasser', defence tells jury

Date
2026-07-17

Stage
Sentence

Primary locality
Dublin

County
Dublin

Summary

The trial of Derek Boyd, 31, and Chantelle Harcourt, 34, continues before the Central Criminal Court. Mr Boyd has pleaded not guilty to the murder of Mark Carroll, 34, at his home in Finglas on June 9, 2024, and to assaulting Megan Rock. Ms Harcourt has pleaded not guilty to an offence of impeding the apprehension or prosecution of a person. In closing submissions, the prosecution alleged that Mr Boyd carried out a determined, murderous attack on Mr Carroll, who had returned to the house to resolve a previous row. The defence argued that Mr Boyd acted out of instinct to protect himself against a trespasser who was threatening him. The jury heard that Mr Boyd was serving the suspended portion of a sentence for the manslaughter of his sister at the time of the alleged offence. The defence counsel suggested that Mr Boyd's subsequent departure to the UK was motivated by the threat of returning to prison for that prior conviction. The trial is ongoing and has not been finalised; it is scheduled to continue on Monday before Ms Justice Melanie Greally and a jury.

Who, what, where, when and why

What: Report matter: Derek Boyd 'acted out of instinct' when he fatally stabbed 'trespasser', defence tells jury. Charges or matters: murdering Mark Carroll (34) at his home on June 9, 2024. Procedural stage: sentence

When:

June 9, 2024 Incident
2026-07-17 Publication

Case subjects

Chantelle Harcourt

Defendant

Plea: Not guilty

Derek Boyd

Accused

Charges: murdering Mark Carroll (34) at his home on June 9, 2024 (Alleged Or Contested)

Plea: Not guilty

Outcome: The jury has heard that Mr Boyd was serving the suspended portion of his sentence for the manslaughter of his sister when he fatally stabbed Mr Carroll. He suggested that this did not follow and that Mr Boyd had a suspended sentence hanging over him like the sword of Damocles', which would come swinging down and have him go back to prison.