Gardai have reopened the investigation into the murder of Grace Livingstone, the housewife shot dead at her home in Malahide, Co Dublin in December 1992. The force’s cold-case unit has begun a full review, including a re-examination of the intelligence, witness statements and forensic evidence.

An initial examination suggests that gardai wrongly suspected the victim’s husband James, a retired tax inspector, of involvement. There are suggestions that the killer may have been a Welsh teenager who was in Malahide on the day.

The review was partly prompted by the findings of an independent report, commissioned by Livingstone, into the force’s handling of the murder investigation. The report, written by a retired British police officer, made recommendations on possible leads that could be followed up.

Officers from the cold-case unit, a branch of the National Bureau of Criminal Investigation (NBCI), met with James Livingstone last month. He was initially identified as a suspect because officers were told the probable time of death was 6pm, at which time Livingstone was in the family home.

He was arrested three months later and questioned by detectives for two days, but released without charge. Last year he settled a High Court action for damages against the state, which cited emotional suffering, negligence, breach of constitutional rights and abuse of legal process. The law suit, which had begun in 1994, was settled after the two sides agreed to issue a public statement that Livingstone is entitled to the full presumption of innocence. The state paid his legal costs.

Livingstone welcomed the decision to reopen the investigation of his wife’s murder. “I think about what happened to Grace every hour of every day. I’ve spent years trying to work out who killed Grace and why,” he said.

“I was wrongly accused. It was a living nightmare for me and my family, but we survived it. I don’t know whether they will find out what happened to Grace after all these years, but it is my hope that they do.”

In 1992, Livingstone was the head of the special investigation unit of the Revenue Commissioners, which targeted IRA terrorists and gangland criminals for tax evasion. He suspected that his wife was killed because of his work, but is now willing to admit it may have been a random act.

“I have no idea what happened. I have spent years considering every possibility, but I don’t know any more,” he said.

The victim was found dead in her bedroom, having been beaten and tied up before being shot in the head at close range with one of Livingstone’s shotguns. Detectives found no sign of a struggle, suggesting she was unconscious when she was shot dead. There were bruises and cuts on her face.

A tiny fingerprint mark was found on the electrical tape used to bind the victim. A forensic examination found it was two separate finger-tip marks superimposed on each other, but of poor quality. It did not belong to Livingstone or any member of his family.

In 1994, a second team of detectives reviewed the findings of the first inquiry and accepted Livingstone’s innocence. The second inquiry found he could not have been the killer, a conclusion that caused acrimony within the garda force.

The second team concluded that it was more likely an intruder had broken into the house and killed Grace Livingstone in an unprovoked attack. A review of the evidence also indicated she died at 4.30pm. Livingstone had left work at 5pm and arrived home about 6pm.

Among the suspects identified by the second inquiry was a “young man with shoulder-length hair” who was seen standing at the door of Livingstone’s home that afternoon. He was later identified as a teenage criminal and drug user from Wales.

“This man returned to Britain after the murder. He had a history of involvement in opportunistic robberies and was also dabbling in drugs at the time,” said a retired detective who investigated the killing. “He was tracked down by British police. When he was interviewed, he gave an account of his movements, but we were never satisfied that he was telling the truth.”

Officers have noted that there was no sign of a break-in at the Malahide house, which suggested the victim had answered the door to her killer.

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