Four people have been arrested in connection with the unsolved murder of Doreen Morris in Holyhead.
The 64 year-old was found dead in her burned-out bungalow at Penrhyn Uchaf on the outskirts of the town in March 1994.
Joseph Carl Westbury was tried for her murder but acquitted the following year - he also denied breaking into the 64 year-old's home on Mill Lane.
Mr Westbury took his own life in 2016.
Three years ago, an inquest into Mrs Morris' death returned a verdict of unlawful killing - she had been stabbed with a fork after disturbing a burglar.
In 2024, North Wales Police launched a major crime review of the case, leading to the arrests of three women and a man on suspicion of perverting the course of justice on Wednesday morning.
Mrs Morris' family has been informed.
Detectives said forensic evidence and a detailed review of witness evidence had provided grounds to question the suspects as part of their review.
Mark Pierce, senior review officer, said: "Throughout the review our thoughts have been with Mrs. Morris’ family, and I hope that this case shows that it doesn’t matter how much time has passed we will always seek out new opportunities to get justice for victims and their families."
Anyone with information regarding the murder should contact North Wales Police on 101 or Crimestoppers anonymously on 0800 555 111, quoting Operation Epose.
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