Ireland Case No. 2048Sexual assault, indecent assault · Co. Limerick
Limerick man awaits sentencing for indecent assault of third victim
Christopher O'Mahony (68), of Kerrykyle, Ardagh, County Limerick, sexually abused his daughter Emma O'Shaughnessy, now 42, from 1993 to 1996 when she was aged 10 to 13, and his sister-in-law Helen Costelloe, now 51, from 1983 to 1989 when she was aged between nine and 15. The abuse emerged after a family meeting on 4 July 2021 when Ms Costelloe disclosed it and Ms O'Shaughnessy said she had also been abused, and O'Mahony presented himself at Henry Street Garda Station with his wife three days later and admitted it. He pleaded guilty to 18 sample counts of sexual and indecent assault from 54 on the indictment and was jailed for nine years by Judge Sinead McMullan at Limerick Circuit Criminal Court on 20 March 2025, and placed on the sex offenders register. In November 2026, a third victim who contacted gardai after reading reports of the case came forward, and O'Mahony pleaded guilty at Limerick Circuit Criminal Court to two counts of indecently assaulting her on two dates in the 1970s when she was aged between five and 12, with sentencing due on 19 November 2026.
- Reportednot reported
- Arrested
- Charged
- In court12 Nov
- Convicted18 Mar
3 reports - Sentenced20 Mar
5 reports
reportedhappened, not reportedlatest stagenot yet
Key facts
consolidated from all reports- What happened
- Christopher O'Mahony sexually and indecently assaulted his daughter Emma O'Shaughnessy and his sister-in-law Helen Costelloe when they were children, including assaulting Ms O'Shaughnessy in the family bathroom under the pretext of applying acne cream and forcing himself on Ms Costelloe in a public toilet in Glin in 1987 and in his car on work rounds.
- O'Mahony has also admitted indecently assaulting a third victim, a young girl, on two dates in the 1970s when she was aged between five and 12.
- Where
- The abuse of Ms Costelloe occurred in locations including the family home in Ballyhahill, O'Mahony's home in Ardagh, the old dispensary in Ballyhahill and the health centre in Glin, and O'Mahony is of Kerrykyle, Ardagh, County Limerick.
- When
- The abuse of Helen Costelloe ran from 1983, when she was nine, until 1989, and the abuse of Emma O'Shaughnessy from 1993, when she was 10, until 1996, when she was 13 and fought back.
- The abuse emerged after a family meeting on 4 July 2021 at which Helen Costelloe disclosed she had been abused and Emma O'Shaughnessy said she had also been abused.
- Investigation
- On 7 July 2021, three days after the family meeting, O'Mahony presented himself at Henry Street Garda Station with his wife and admitted the abuse, with Detective Garda James Muldowney of the Limerick Garda Divisional Protective Services Unit leading the investigation.
- The third victim contacted gardai after reading media court reports about O'Mahony abusing his daughter and sister-in-law, and Detective Garda James Muldowney visited O'Mahony at Midlands Prison to put the fresh allegations to him.
- Charges
- O'Mahony was charged with 54 counts on indictment and pleaded guilty to 18 sample counts of sexually and indecently assaulting the two girls, reported as 10 or 11 sample indecent assaults on his sister-in-law and seven sample sexual assault counts on his daughter.
- O'Mahony pleaded guilty to two counts of indecently assaulting the third victim on two dates in the 1970s.
- In court
- The case was heard at Limerick Circuit Criminal Court before Judge Sinead McMullan, who lifted a reporting ban on O'Mahony's name after the victims waived their anonymity.
- Sentence
- On 20 March 2025, Judge Sinead McMullan jailed O'Mahony for a total of nine years for sexually assaulting his daughter and sister-in-law.
- O'Mahony was placed on the sex offenders register, reported as for life, and was remanded in custody to be sentenced for the 1970s indecent assaults on 19 November 2026.
- Other details
- O'Mahony, a former rates collector with Limerick County Council, also beat and psychologically abused his daughter, controlling when she could go to the toilet and how much toilet paper she could use, causing urinary tract infections, and warned the children not to talk about the abuse.
- The emergence of the abuse caused a split in the family, Ms O'Shaughnessy said her mother and two sisters supported her abuser, Ms Costelloe waited three years on a waiting list to see a counsellor after contacting a rape crisis centre, and a letter of apology from O'Mahony was handed in to the judge.
92 statements extracted from the articles
- whatO'Mahony sexually assaulted Ms O'Shaughnessy in the bathroom of their home under the pretext of applying acne cream. (irishtimes.com)
- whatO'Mahony forced himself on Ms Costelloe as she was using a public toilet in Glin in 1987. (irishtimes.com)
- whatThe judge highlighted offences including O'Mahony masturbating and ejaculating onto his daughter and sexually assaulting her with his hand on the pretext of applying acne cream. (limerickpost.ie)
- whatO'Mahony forced himself on Ms Costelloe while she was using a public toilet. (limerickpost.ie)
- whatO'Mahony also beat and psychologically abused his daughter, controlling when she was allowed go to the toilet and how much toilet paper she could use, causing urinary tract infections. (limerickpost.ie)
- whereO'Mahony came to live in the family home in Ballyhahill while he built a house in Ardagh. (limerickleader.ie)
- whereO'Mahony is of Kerrykyle, Ardagh, County Limerick. (limerickpost.ie)
- whereThe abuse of Ms Costelloe occurred in locations including the family home in Ballyhahill, O'Mahony's home in Ardagh, the old dispensary in Ballyhahill and the health centre in Glin. (limerickleader.ie)
- whenThe abuse of Helen Costelloe started in 1983 when she was nine and continued until 1989 when she was 15. (limerickleader.ie)
- whenThe abuse of Emma O'Shaughnessy began in 1993 when she was 10 and ended in 1996 when she was 13. (limerickleader.ie)
- whenThe abuse occurred from when the girls were aged nine and 10 on dates in the 1980s and 1990s. (limerickpost.ie)
- whenThe abuse emerged after a family meeting on July 4th, 2021, at which Helen Costelloe disclosed she had been abused and Emma O'Shaughnessy said she had also been abused. (irishtimes.com)
- whenMs Costelloe was sexually abused by O'Mahony when aged between nine and 14. (irishtimes.com)
- whenMs O'Shaughnessy was abused by her father when aged 10 to 13. (irishtimes.com)
- whenThe abuse occurred on dates in the 1980s and 1990s. (thejournal.ie, limerickpost.ie)
- whenThe abuse emerged after a family meeting on 4 July 2021 when Helen Costelloe disclosed she had been abused. (thejournal.ie)
- whenHelen Costelloe was sexually abused from the ages of nine to 14. (limerickpost.ie)
- whenEmma O'Shaughnessy was sexually assaulted by her father from when she was aged 10 to 13. (limerickpost.ie)
- whenOn July 7, 2021, three days after the family meeting, O'Mahony accompanied by his wife presented himself at Henry Street Garda Station and admitted the abuse. (limerickpost.ie)
- whenThe victim was aged between five and 12 years when O'Mahony abused her. (limerickpost.ie)
- causeThe sexual abuse emerged after a family meeting on July 4, 2021, when Helen Costelloe disclosed she had been abused. (limerickpost.ie)
- causeThe abuse emerged after a family meeting when Helen Costelloe disclosed she had been abused and Emma O'Shaughnessy told her family she too had been abused. (limerickpost.ie)
- investigationO'Mahony handed himself into Henry Street garda station three days after a family meeting in July 2021 and the investigation commenced. (limerickleader.ie)
- investigationOn July 7, 2021, O'Mahony presented himself at Henry Street Garda Station and told Gardaí he was handing himself in. (limerickpost.ie)
- investigationThree days after the family meeting, O'Mahony, accompanied by his wife, presented himself at Henry Street Garda station and admitted the abuse. (irishtimes.com)
- investigationThree days later, on 7 July 2021, O'Mahony presented himself at Henry Street Garda Station with his wife and admitted the abuse. (thejournal.ie)
- investigationThe victim contacted Gardaí about the abuse 54 years earlier after reading media court reports about O'Mahony abusing his daughter and sister-in-law. (limerickpost.ie)
- investigationDetective Garda James Muldowney visited O'Mahony at Midlands Prison and put the fresh allegations to him. (limerickpost.ie)
- chargeO'Mahony pleaded guilty to 10 sample indecent assaults and one sexual assault of his sister-in-law and seven sample counts of sexual assault on his daughter, with 54 counts on the indictment. (limerickleader.ie)
- chargeChristopher O'Mahony was charged with 54 counts on indictment and pleaded guilty to 18 sample counts of sexually assaulting and indecently assaulting two girls. (limerickpost.ie)
- chargeO'Mahony was charged with 54 counts on indictment and pleaded guilty to 18 sample counts of sexually and indecently assaulting the girls on dates in the 1980s and 1990s. (irishtimes.com)
- chargeO'Mahony was charged with 54 counts on indictment and pleaded guilty to 18 sample counts of sexually assaulting and indecently assaulting the two girls. (thejournal.ie, limerickpost.ie)
- chargeO'Mahony pleaded guilty to 11 sample indecent assaults on his sister-in-law and seven sample counts of sexual assault on his daughter, with 54 counts on the indictment. (limerickleader.ie)
- chargeChristopher O'Mahony pleaded guilty to two counts of indecently assaulting a young girl on two dates in the 1970s. (limerickpost.ie)
- courtJudge Sinead McMullan remanded O'Mahony in custody and will pass judgment on Thursday. (limerickleader.ie)
- courtThe sentencing hearing took place at Limerick Circuit Criminal Court. (limerickpost.ie)
- courtO'Mahony said through his barrister that he did not disagree with any of the evidence against him. (limerickpost.ie)
- courtThe case was heard at Limerick Criminal Circuit Court on Friday before Judge Sinead McMullan. (limerickleader.ie)
- courtThe sentencing took place at Limerick Circuit Criminal Court on Thursday before Judge Sinéad McMullan. (irishtimes.com)
- courtThe sentence was handed down at Limerick Circuit Criminal Court by Judge Sinead McMullan. (thejournal.ie)
- courtJudge Sinead McMullan at Limerick Circuit Criminal Court lifted a ban preventing the media from reporting O'Mahony's name. (limerickpost.ie)
- courtJudge Sinead McMullan presided and imposed the sentence. (limerickleader.ie)
- courtJudge Mary Morrissey remanded O'Mahony in continuing custody to finalise his sentence on November 19. (limerickpost.ie)
- sentenceO'Mahony was remanded in custody for sentencing on Thursday, March 20. (limerickpost.ie)
- sentenceJudge McMullan remanded O'Mahony in custody and will pass judgment on Thursday. (limerickleader.ie)
- sentenceChristopher O'Mahony was jailed for nine years for sexually assaulting his daughter and sister-in-law. (irishtimes.com)
- sentenceChristopher O'Mahony was jailed for nine years. (thejournal.ie, limerickpost.ie)
- sentenceChristopher O'Mahony was jailed for a total of nine years at Limerick Criminal Circuit Court. (limerickleader.ie)
- sentenceO'Mahony is placed on the sex offenders register. (limerickleader.ie)
- otherO'Mahony was placed on the sex offenders register two weeks ago. (limerickleader.ie)
- otherThe victims waived their anonymity so O'Mahony can be named. (limerickleader.ie)
- otherThe emergence of the sexual abuse caused a split in the family. (limerickleader.ie)
- otherHis daughter Emma O'Shaughnessy and her aunt Helen Costelloe waived their right to anonymity, allowing him to be named. (limerickpost.ie)
- otherO'Mahony was a former rent collector with Limerick County Council. (limerickpost.ie)
- otherO'Mahony also sexually assaulted Ms Costelloe in his car on his work rounds around Limerick. (limerickpost.ie)
- otherThe abuse of Ms O'Shaughnessy began under the pretence of treating her with ointment for a rash in the bathroom of the family home. (limerickpost.ie)
- otherThe sexual abuse of Ms O'Shaughnessy stopped when she was 13 and fought back, pushing O'Mahony off at their family home. (limerickpost.ie)
- otherThe attacks on Ms Costelloe stopped when, aged 14, she fought back during a work trip. (limerickpost.ie)
- otherProsecuting Garda Detective James Muldowney of the Limerick Garda Divisional Protective Services Unit told the court there is a split in the family. (limerickpost.ie)
- otherThe two victims waived their anonymity, allowing O'Mahony to be named. (limerickleader.ie)
- otherThe emergence of the abuse caused a split in the family. (limerickleader.ie)
- otherA letter of apology from O'Mahony was handed into the judge by his barrister. (limerickleader.ie)
- otherO'Mahony began abusing Ms Costelloe after he married her sister and moved into their family home, abusing her while she washed his hair. (irishtimes.com)
- otherO'Mahony warned the children not to talk about the abuse, telling Ms Costelloe it was their secret and Ms O'Shaughnessy to keep her mouth shut. (irishtimes.com)
- otherThe court was told O'Mahony did not disagree with any of the evidence against him. (irishtimes.com)
- otherMs Costelloe said she was three years on a waiting list to see a counsellor after seeking help at a rape crisis centre. (irishtimes.com)
- otherHelen Costelloe was abused from when she was aged nine to 14. (thejournal.ie)
- otherEmma O'Shaughnessy was sexually assaulted by her father from when she was aged 10 until 13. (thejournal.ie)
- otherO'Mahony also beat and psychologically abused his daughter and controlled when she could go to the toilet, causing urinary tract infections. (thejournal.ie)
- otherThe judge said O'Mahony used his daughter and sister-in-law as objects and that it was a huge breach of trust. (thejournal.ie)
- otherO'Mahony warned the victims not to talk about the abuse. (thejournal.ie, limerickpost.ie)
- otherO'Mahony was a former council rates collector. (thejournal.ie)
- otherDetective Garda James Muldowney of the Limerick Garda Divisional Protective Services Unit led the investigation. (thejournal.ie)
- otherThe victims waived their right to anonymity and wanted O'Mahony identified. (thejournal.ie)
- otherHelen Costelloe said she was three years on a waiting list to see a counsellor after seeking help at a rape crisis centre. (thejournal.ie)
- otherO'Mahony began abusing Helen Costelloe after marrying her sister, who is 12 years her senior, and moving into her family home. (thejournal.ie)
- otherO'Mahony instructed the court that he did not disagree with any of the evidence against him. (thejournal.ie, limerickpost.ie)
- otherMs Costelloe waited three years to see a counsellor after contacting a rape crisis centre. (irishmirror.ie)
- otherDetective Garda James Muldowney led the investigation. (irishmirror.ie)
- otherO'Mahony is 67 and of Kerrykyle, Ardagh, County Limerick. (limerickpost.ie)
- otherThe victims, his daughter Emma O'Shaughnessy and his sister-in-law Helen Costelloe, waived their right to anonymity. (limerickpost.ie)
- otherO'Mahony began abusing Ms Costelloe after marrying her sister, who is 12 years her senior, and moving into her family home. (limerickpost.ie)
- otherMs Costelloe was three years on a waiting list to see a counsellor after seeking help at a rape crisis centre. (limerickpost.ie)
- otherLily Buckley prosecuted the case. (limerickpost.ie)
- otherMs O'Shaughnessy told the court her mother and two sisters had chosen to support her abuser. (limerickpost.ie)
- otherHelen Costelloe called a family meeting in July 2021 after telling family members of the abuse, at which Emma O'Shaughnessy revealed she too had been abused. (limerickleader.ie)
- otherBoth victims waived their anonymity so O'Mahony could be named. (limerickleader.ie)
- otherThe emergence of the sexual abuse caused a civil war and complete fracture within the family. (limerickleader.ie)
- otherO'Mahony is serving a nine-year jail sentence for sexually abusing his daughter and sister-in-law. (limerickpost.ie)
- otherThe victim suffered serious mental health difficulties as a direct result of the abuse. (limerickpost.ie)
- otherO'Mahony has already been placed on the sex offender's register for life. (limerickpost.ie)
- otherLast year O'Mahony admitted 18 sample charges of sexual and indecent assault arising out of 54 charges relating to his daughter and sister-in-law between the 1980s and 1990s. (limerickpost.ie)
The reporting
newest first- 12 Nov2026‘Monster’ paedophile facing more jail time after third victim comes forward
Adds a third victim from the 1970s to the earlier case: O'Mahony has pleaded guilty to two counts of indecent assault and awaits sentencing on 19 November while serving his nine-year sentence.
convicted, Christopher O'Mahony, 68, male, namedChristopher O'Mahonyvictim, femaleother, James Muldowney, maleJames Muldowney - 21 Mar2025BREAKING: Limerick 'paedophile' and 'monster' jailed for sexually abusing daughter and sister-in-law
Adds the sentencing report: nine-year total sentence, guilty plea to 11 sample indecent assaults on the sister-in-law and seven sample sexual assault counts on the daughter, 54 counts on the indictment, abuse timeline, family meeting in July 2021, and the garda handover.
convicted, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, 42, femaleEmma O'Shaughnessyvictim, Helen Costelloe, 51, femaleHelen Costelloeother, Sinead McMullanSinead McMullanother, Lily BuckleyLily Buckleyother, Brendan GillBrendan Gillother, James MuldowneyJames Muldowney - 21 Mar2025‘Monster’ and 'paedophile' father jailed for nine years for sex abuse of daughter and sister-in-law
Adds the sentence of nine years, the court and judge, the plea to 18 sample counts, the time of the offences, the delayed reporting to gardaí, and statements from both victims calling for more supports.
convicted, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, femaleEmma O'Shaughnessyvictim, Helen Costelloe, femaleHelen Costelloeother, Sinead McMullanSinead McMullanother, Lily BuckleyLily Buckley - 20 Mar2025'Monster, paedophile' dad jailed as victims of horrific abuse speak out
Reports the nine-year sentence and includes post-sentencing statements from both victims calling for improved victim services, as well as the judge's remarks on the most serious offences and the breach of trust.
convicted, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, femaleEmma O'Shaughnessyvictim, Helen Costelloe, femaleHelen Costelloeother, Sinead McMullan, femaleSinead McMullanother, James Muldowney, maleJames Muldowneyother, Lily Buckley, femaleLily Buckleyother, Brendan Gill, maleBrendan Gill - 20 Mar2025Man jailed for nine years for sexually abusing daughter and sister-in-law
Reports the nine-year sentence and the victims' statements in Limerick Circuit Criminal Court on 20 March 2025, and adds details of the abuse, the 2021 disclosure and the lifting of the reporting ban on the accused's name.
convicted, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, femaleEmma O'Shaughnessyvictim, Helen Costelloe, femaleHelen Costelloeother, Sinead McMullan, femaleSinead McMullanother, James Muldowney, maleJames Muldowneyother, Lily Buckley, femaleLily Buckleyother, Brendan Gill, maleBrendan Gill - 20 Mar2025‘Monster’ jailed for nine years for sexually abusing daughter and sister-in-law
Provides extensive sentencing detail: the judge's remarks, victim-impact statements, the family meeting on 4 July 2021 that triggered disclosure, O'Mahony's self-surrender at Henry Street Garda station three days later, specific incidents including the Glin public toilet assault in 1987 and the bathroom acne-cream pretext, and the victims' calls for better rape crisis centre supports.
convicted, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, femaleEmma O'Shaughnessyvictim, Helen Costelloe, femaleHelen Costelloeother, Sinéad McMullanSinéad McMullanother, Lily BuckleyLily Buckley - 19 Mar2025‘Civil war’ breaks out in Limerick family after victims reveal ‘secret’ of sexual abuse
Reports the guilty plea, the counts pleaded to (from 54 on the indictment), the dates of abuse, the victims' names and ages after they waived anonymity, and that sentencing is due this week. Adds the sex offenders register detail.
accused, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, 42, femaleEmma O'Shaughnessyvictim, Helen Costelloe, 51, femaleHelen Costelloeother, Lily BuckleyLily Buckleyother, James MuldowneyJames Muldowneyother, Pat WhymsPat Whymsother, Sinead McMullanSinead McMullan - 18 Mar2025Limerick man unmasked as ‘monster’ who sexually abused daughter and sister-in-law
Reports the guilty plea, the victims' court statements and the remand for sentencing on 20 March 2025. The existing case records the later nine-year sentence.
convicted, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, femaleEmma O'Shaughnessyvictim, Helen Costelloe, 52, femaleHelen Costelloeother, Lily BuckleyLily Buckleyother, James Muldowney, maleJames Muldowney - 18 Mar2025Controlling 'monster' sexually abused daughter and sister-in-law and rationed toilet paper, Limerick court hears
Reports the guilty plea, the counts pleaded to, the remand in custody and that sentencing was due on the Thursday after the hearing. The existing case records the later nine-year sentence.
accused, Christopher O'Mahony, 67, male, namedChristopher O'Mahonyvictim, Emma O'Shaughnessy, 42, femaleEmma O'Shaughnessyvictim, Helen Costelloe, 51, femaleHelen Costelloeother, Lily BuckleyLily Buckleyother, James MuldowneyJames Muldowneyother, Sinead McMullanSinead McMullan
This page is put together automatically from the reports listed above. A charge is not a conviction. If something here is wrong or out of date, report it.