Thirty years ago, tragedy struck as an 82-year-old woman was discovered covered in blood, cowering against her stove following a raid on her Martlesham bungalow.

She died 11 days later and her murder remains a mystery to this day, with Suffolk police continuing to search for new clues in the investigation.

On February 11, 1993, a concerned neighbour broke in through a window and found Doris Shelley, 82, in a dazed and confused state.

Covered in her own blood from an attack with a blunt object, Mrs Shelley lost consciousness upon being discovered and died in a hospital bed on February 22.

East Anglian Daily Times: Doris Shelley was found covered in her own blood in her Martlesham bungalow.Doris Shelley was found covered in her own blood in her Martlesham bungalow. (Image: Archant)

Police determined that, sometime between 2pm on Wednesday, February 10 and 12:45pm on Thursday, February 11, an unknown person or persons had broken into the property possibly through a bedroom window.

Just 18 months earlier, Mrs Shelley was the victim of a violent robbery at her home in which £12,637 was stolen.

READ MORE: Five of Suffolk's most mysterious unsolved police cases

As a result of this occurrence, she was noted to be very "security conscious," meaning she would not leave the house and had a number of people to help her with tasks such as errands.

Suffolk police officers believed attackers were also "looking for valuables to take" during the second fatal incident.

A number of people were arrested in connection with the burglary, but no charges were ever brought against them.

East Anglian Daily Times: Doris Shelley died as a result of her injuries in a hospital bed 11 days after the attack.Doris Shelley died as a result of her injuries in a hospital bed 11 days after the attack. (Image: Suffolk Constabulary)

On the 25th anniversary of her death in 2018, a police appeal was issued and investigators received a "potentially interesting" tip-off.

However, a year after the possible break through, officers said nothing came of the lead and details of this information were never released to the public.

As part of the anniversary appeal, 70 officers revisited 397 exhibits from the original investigation and a reward of £10,000 was put out for any information on the murder.

Now, 30 years on, Doris Shelley's case is subject to continual review by Suffolk Constabulary as they search for new lines of investigation.