Courts / Roscommon / Report

Garda murderer claims psychiatric evidence contradicted legal test for insanity

Date
2026-03-19
Stage
Appeal
Primary locality
Castlerea
County
Roscommon

Summary

Stephen Silver, a 49-year-old motorbike mechanic from Aughaward, Foxford, Co Mayo, appealed his conviction for the murder of Garda Colm Horkan. Silver, who pleaded not guilty to killing the garda knowing or being reckless as to whether he was acting in the course of his duty, argued that the State's psychiatric evidence contradicted the legal test for insanity under the Criminal Law (Insanity Act 2006). His counsel contended that the prosecution expert's testimony regarding Silver's capacity to form intent improperly excluded the possibility of diminished responsibility. The prosecution rebutted this, stating the expert merely identified purposeful actions as one factor in assessing mental capacity and that the trial judge's direction was appropriate. The appeal hearing was presided over by Mr Justice John Edwards, with Mr Justice Patrick McCarthy and Ms Justice Isobel Kennedy. The court reserved judgment, meaning the matter was adjourned and not concluded. Silver was originally sentenced in April 2023 by Ms Justice Tara Burns to life imprisonment with a minimum term of 40 years. The trial evidence included conflicting psychiatric opinions on whether Silver's bipolar disorder contributed to his actions when he shot Garda Horkan eleven times in Castlerea, Co Roscommon, on June 17, 2020.

Who, what, where, when and why

What: Report matter: Garda murderer claims psychiatric evidence contradicted legal test for insanity. Charges or matters: the murder of Gda Horkan knowing or being reckless as to whether he was a member of An Garda Siochana acting in the course of his duty. Procedural stage: appeal

When:

Case subjects

Stephen Silver

Appellant

Charges: the murder of Gda Horkan knowing or being reckless as to whether he was a member of An Garda Siochana acting in the course of his duty (Alleged Or Contested)

Plea: Not guilty

Outcome: In April 2023, Silver was jailed for life by Ms Justice Tara Burns with a minimum time to be served of 40 years.; Mr Justice John Edwards, presiding with Mr Justice Patrick McCarthy and Ms Justice Isobel Kennedy, reserved judgment.

Places mentioned

Residence
Secondary Mention
Facility
  • Central Mental Hospital
Journey Or Route

Topics

Stage Appeal Violent Crime

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