The dad of a baby boy brutally killed by his mum or her lover says the fight to get justice has "ruined my life".
Sam Harry was just 20 months old when he sustained a severe brain injury while his mum Deanna Buffham and Ryan Bate were supposed to be looking after him.
Police arrested the couple on suspicion of murder after the youngster's head was smashed against a surface with a significant level of force - later compared to a 60mph car crash, the Sun Online reports.
According to a coroner, Sam was killed unlawfully - and police decided that either Buffham or Bate inflicted the blow that lead to the baby boy's death.
But the pair blamed each other for the youngster's death, and walked free because it couldn't be proved who dealt the strike that killed him.
Now nine years after Sam's death, his dad Nicholas Harry, from Houghton Regis in Bedfordshire, said he is still fighting for justice.
He told The Sun Online: "I could have given up but I have to do everything I can for Sam - I always will.
"This has ruined my life. I had to take a step back and reinvent myself as my life spiralled."
Nicholas split with Buffham shortly after Sam was born in an "extremely tough" break up, he said.
Despite being told he had no chance of winning full custody of his son, Nicholas put his all into a court case to get his son under his care - even selling his house to cover £14,000 in legal costs.
But he lost favour with the court after submitting a document about Buffham's troubling behaviour during their relationship.
Buffham won full custody of the lad, starting the series of events that lead to his tragic death in April 2013.
Nicholas was awarded limited access and could see his son every second weekend and on the Wednesday of the third week of the month.
He said he was supposed to be looking after his son on the weekend he died, but Buffham was a no-show.
If Sam had been with him, he would still be alive, he says.
Sam was rushed to A&E on April 21 after an "emergency" at home before doctors revealed he'd suffered a bleed on the brain.
It later emerged that the youngster had been dealt a horrific blow in the 11 hours before paramedics were actually called by either Buffham or Bate.
Tests later showed the toddler had been subjected to an "inflicted injury" which caused "huge" brain damage.
After being arrested on suspicion of murdering the boy the pair - who split shortly after - offered no explanation for how the toddler suffered the devastating head injuries.
At the time police knew either of them killed the boy, but neither could be charged because of a legal loophole.
At an inquest in 2015, both Buffham and Bate admitted that one of them had inflicted the injuries that killed the boy.
Coroner Martin Oldham asked the pair almost identical questions when they gave evidence separately.
He began by confirming that one of them inflicted the injuries on Sam.
Buffham replied: "Yes I accept that," and Bate said: "Yes."
Coroner Oldham then asked directly if they were responsible for the attack.
Buffham replied: "Absolutely not," and Bate said: "No."
He finished by asking if this meant the other must have inflicted Sam's injuries.
Buffham replied: "I can only assume so," and Bate said: "If there's two people and it wasn't one of them it must have been the other one, so yes."
Buffham, who appeared at the inquest via videolink, revealed she and Bate split six months after Sam's death.
She told the hearing: "It took time to realise that I had introduced someone into Sam's life that harmed him.
"It did cause concern and on Boxing Day we had an argument and I remember calling him a murderer.
While recording his verdict Coroner Oldham said: "There are on the medical evidence only two people who could have caused the fatal injuries - Miss Buffham and Mr Bate.
"I have to say I place little reliance on the flawed accounts they have given on each and every occasions, they simply do not know truth from lie.
"Ryan Bate and Deanna Buffham do know the truth they have simply failed to come forward with that account.
"I have not the slightest bit of doubt at all that Sam Harry was unlawfully killed while being cared for by Ryan Bate and Deanna Buffham."
At the end of the hearing, Nicholas wept as the verdict was read out before calling on the Crown Prosecution Service to review the decision to let them walk free.
He said: "There's two people out there on the streets at the moment and one of them has killed a chil d."
