Four people arrested in connection with the unsolved murder of Doreen Morris have been released under investigation.
Three women and a man were questioned on suspicion of perverting the course of justice following a case review into the death of the 64 year-old, whose body was found in her burned-out bungalow near Holyhead in March 1994.
North Wales Police said the suspects, all from the region, were arrested and released last Wednesday.
Joseph Carl Westbury was tried for Mrs Morris' murder the following year but was found not guilty - 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.
Detectives said fresh evidence emerging from a major case review, which was launched two years ago, provided grounds to question the suspects as part of their review.
A North Wales Police spokesperson said Mrs Morris' family have been kept informed and the investigation is ongoing.
Anyone with any information in relation to the case is asked to contact us on 101 or alternatively via Crimestoppers quoting Operation Epose, North Wales Police.
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