Casepin
Back to cases

Case file

Grangegorman killings

SOLVED1997Orchard View, Grangegorman (former St Brendan's Hospital grounds)2 SOURCESUPDATED JUL 2026

Documents violence · sexual violence — written to inform, not to shock.

Illustrative

Sylvia Sheils and Mary Callinan were killed during the night of 6-7 March 1997 in sheltered accommodation at Orchard View, on the grounds of the former St Brendan's Hospital in Grangegorman, Dublin. Both women, aged 59 and 61, had lived in the community after earlier being patients at the psychiatric hospital. They were found the following morning by a fellow resident. Post-mortem examinations established that each woman had sustained multiple stab wounds and further mutilation; the state pathologist said the injuries were beyond his professional experience.

The investigation initially focused on Dean Lyons, a 24-year-old man with a heroin addiction who had been assessed in childhood as having a low IQ and whom experts later found to be highly suggestible. In July 1997, after gardai heard that he had spoken about the killings, he was questioned and, while experiencing withdrawal, admitted to the murders. His early account did not fit the evidence: he was wrong about the location, the number of victims, and the weapons used. His parents and brother told investigators that he was prone to inventing stories and confessing to things he had not done. Lyons was nevertheless charged and held on remand.

Shortly afterwards Mark Nash, then under investigation for the killing of Carl and Catherine Doyle in County Roscommon in August 1997, admitted to the Grangegorman killings and gave details that were not publicly known, before retracting his statement. With Lyons already charged, opinion within the force divided. By early 1998 investigators concluded that Lyons had no involvement, and the charges against him were withdrawn on 29 April 1998 after roughly nine months in custody. Lyons died in 2000, before his name was cleared through later inquiries. In 2005 the Garda Siochana apologised to his family, and a Commission of Investigation reported in 2006 that his false confession arose from personal vulnerabilities compounded by leading questions during interview.

Nash was convicted of the Roscommon murders in 1998 and sentenced to life imprisonment. Advances in DNA analysis in 2009 identified both victims' blood on a jacket linked to him, and he was charged with the Grangegorman killings that October. After a lengthy trial at the Central Criminal Court, he was found guilty of the murders of Sylvia Sheils and Mary Callinan and sentenced to life on 20 April 2015. The Court of Appeal upheld the conviction in 2018. The case is widely cited in Ireland as a significant miscarriage of justice for the wrongful charging of an innocent man.

Key facts

Victims
Sylvia Sheils, Mary Callinan
Date
1997
Location
Orchard View, Grangegorman (former St Brendan's Hospital grounds)
Case status
solved

Case timeline

  1. 1997-03-06

    Sylvia Sheils and Mary Callinan are killed at Orchard View, Grangegorman, Dublin.

  2. 1997-03-07

    The two women's bodies are discovered by a fellow resident.

  3. 1997-07-26

    Dean Lyons is arrested and makes a false confession to the killings while in heroin withdrawal.

  4. 1997-08

    Mark Nash kills Carl and Catherine Doyle in County Roscommon; he later admits to the Grangegorman killings and then retracts the admission.

  5. 1998-04-29

    The charges against Dean Lyons are withdrawn after about nine months on remand.

  6. 1998-10

    Mark Nash is convicted of the Roscommon murders and sentenced to life imprisonment.

  7. 2000

    Dean Lyons dies before his name is cleared through later inquiries.

  8. 2005

    The Garda Siochana apologises to the Lyons family.

  9. 2006-09-01

    The Commission of Investigation into the Dean Lyons case publishes its report, finding the confession was false.

  10. 2009-07

    DNA analysis identifies both victims' blood on a jacket linked to Mark Nash.

  11. 2009-10

    Mark Nash is charged with the Grangegorman killings.

  12. 2015-04-20

    Mark Nash is found guilty of the murders of Sylvia Sheils and Mary Callinan and sentenced to life imprisonment.

  13. 2018-05-08

    The Court of Appeal upholds Mark Nash's conviction.

Best coverage

No approved coverage links are attached yet.

People

  • Sylvia Sheils

    VICTIM

    One of two women killed at Orchard View, Grangegorman, on the night of 6-7 March 1997; aged 59. She had earlier been a patient at St Brendan's Hospital and was living in sheltered accommodation.

    citation on file

  • Mary Callinan

    VICTIM

    One of two women killed at Orchard View, Grangegorman, on the night of 6-7 March 1997; aged 61. She had earlier been a patient at St Brendan's Hospital and was living in sheltered accommodation. Her surname is also recorded as Callanan.

    citation on file

  • Mark Nash

    CONVICTED

    Convicted at the Central Criminal Court in April 2015 of the murders of Sylvia Sheils and Mary Callinan and sentenced to life imprisonment; the conviction was upheld on appeal in 2018. He had earlier been convicted of two 1997 murders in County Roscommon. DNA evidence identified in 2009 linked him to the Grangegorman victims.

    citation on file

  • Dean Lyons

    EXONERATED

    Wrongly charged with the killings in 1997 after making a false confession while in heroin withdrawal; held on remand for about nine months before the charges were withdrawn on 29 April 1998. A 2006 Commission of Investigation found the confession was false, and the Garda Siochana apologised to his family in 2005. He died in 2000 before his name was cleared. He had no involvement in the killings.

    citation on file

Places

Orchard View, Grangegorman (former St Brendan's Hospital grounds)

53.3563, -6.2822

View on the map

Common questions

What happened to the victim?
Sylvia Sheils and Mary Callinan were killed in Grangegorman, Dublin, in March 1997. An innocent man, Dean Lyons, falsely confessed and was wrongly charged before the charges were withdrawn; Mark Nash was later convicted of the murders in 2015.
Where did the killings happen?
Orchard View, Grangegorman (former St Brendan's Hospital grounds).
Who was convicted?
Mark Nash (Convicted at the Central Criminal Court in April 2015 of the murders of Sylvia Sheils and Mary Callinan and sentenced to life imprisonment; the conviction was upheld on appeal in 2018. He had earlier been convicted of two 1997 murders in County Roscommon. DNA evidence identified in 2009 linked him to the Grangegorman victims.).
What is the current status of the case?
Status: solved. Last verified July 2026.

Sources

  1. Grangegorman killingswikipedia · Wikipedia · 2026-07-05
  2. Court of Appeal upholds Nash conviction for Grangegorman murdersnews · The Irish Times · 2026-07-05

Last verified JUL 2026

More cases in Ireland