In 2022, O’Brien met Saunders’ sister and nephew as part of a TV documentary, something which he said had “a profound effect” on him.
His recent trip to the grave to leave flowers spurred him on to try and raise money for a new headstone and give it to the family.
“I really feel for them – for the pain they’ve gone through,” he said.
Despite never meeting Saunders, O’Brien said he was someone he had learnt a lot about over the years.
“I just want to do whatever I can, not only to catch the real killer, but also to remember Philip Saunders, because I think he deserves to be remembered,” he said.
“He was a good guy – nobody’s got a bad word to say about Mr Saunders – he was a hardworking man.”
Saunders was previously described as “a loving brother and a caring uncle” by his brother Ted and sister-in-law Marge, who lamented the fact that he would not enjoy the retirement he had worked so hard for.
O’Brien has spent much of his life since his release campaigning for victims of miscarriages of justice.
Last year, he lost a legal challenge to reclaim money he was charged for bed and board during the 11 years he spent behind bars.
O’Brien received £692,900 in compensation in 2002, three years after his release, but then had £37,500 deducted from his compensation to cover “saved living expenses” while in prison.
The policy was scrapped in 2023 but the UK government said it would not be applied retrospectively.