A 41-year-old man literally got away with murder for 20 years -- until he had an attack of conscience and confessed to police.

Officially, Margot Seery’s death in October 1994 was regarded as being caused by asphyxiation in her own alcohol-induced vomit. Gardai and medical authorities did not suspect any other cause until Howard Kelly walked into a police station last year to make a confession.

The amazing details were outlined at the Central Criminal Court in Dublin on Monday when Kelly, now aged 41, pleaded guilty to murder and was given a life sentence in jail.

Brendan Grehan, prosecuting, told the court how Kelly, most recently living with his wife and two children at Naas, Co. Kildare, faced a murder charge in “a highly unusual case” in which death was not considered “suspicious” when it happened.

The court heard that 48-year-old Seery’s body was found fully clothed on her bed in her apartment in Rathmines, Co. Dublin.

A post mortem indicated there was no suspicious circumstance attached to the death and that it was caused by asphyxia due to inhalation of vomit from alcohol. Her body was buried at Rathkeale Cemetery in Co. Limerick.

Twenty years later college-educated Kelly walked into Rathmines Garda Station “unannounced” in July 2014 and confessed to murder.

He said he was with a friend and was approached by two women in October 1994 and he went with one of the women to a house in Rathmines.

He told Gardai that he had “felt threatened” by the woman and killed her by strangling and then lifted her onto the bed.

His confession added, “I did so intentionally and it was not by accident and I have a heavy heart.”

He said he “had a rush of blood to the head,” and something came over him and he felt compelled to take off his shirt and wrestle her to the ground, put his knees on her arms and strangle her to death.

Kelly told Gardai he had come forward as he had thoughts of ending things and his children were having nightmares. He also apologized to Gardai for not coming to them sooner.

In a statement to the court, Seery’s daughter Niamh Holliday, who was 12 when she died, said she was relieved that the truth had finally come out.

Her statement said, “I hate that I had that anger towards her for so long and none of this was her fault… In the last year I have gone through so many emotions with this case. It was mainly anger as I shouldn’t have had to believe a lie for 20 years. For that I am grateful to Howard Kelly for actually coming forward with his confession.”

Seery’s brother Pa Guinane told the court in a victim impact statement that for 20 years they believed “Margot caused her death” which upset her mother and family.