A mother and her boyfriend have been found guilty of causing the death of a five-month-old baby boy in Kent.
Eli Cox's mother Katherine Cox, 33, and her boyfriend Danny Shepherd, known as "Pickle", both denied causing or allowing his death in April last year.
Maidstone Crown Court heard Eli died from a "catastrophic" injury to the head, but he also had 28 fractures.
A serious case review is now under way to establish if his death could have been prevented by the authorities.
Shepherd and Cox, of Lapwing Close, Minster-on-Sea, on the Isle of Sheppey, were both found guilty of causing or allowing the death of a child and causing or allowing serious physical injury to a child.
They were both also found guilty of possessing a class B drug.
Sentencing will take place at a later date as a psychiatric report is being prepared.
During the trial, Shepherd, 25, said he saw Eli gasping and was "trying to save him" with CPR, while mother-of-nine Cox said she was told to hang Eli "upside down and shake him" when he turned blue and stopped breathing.
But a specialist bone pathologist told the court the injuries to Eli's bones were "caused by pulling, twisting, grasping and crushing", inflicted on separate occasions from when he was 10 weeks old to two weeks before his death.
A hair sample showed Eli was also "regularly exposed to amphetamine and occasionally to cocaine".
Police were called to the home weeks before Eli's death, and Kent County Council confirmed the family was known to them.
A KCC spokesman added: "The siblings are now being appropriately cared for following the conclusion of care proceedings."
The serious case review will establish what, if any, failings were made by the authorities.
'Beating him up'
Neighbours spoke of frequent commotion coming from Cox and Shepherd's home.
One, Abbie Jackson, recalled Cox banging on her door in the early hours and asking where "Pickle" was.
Ms Jackson said: "Five minutes later she was beating him up round the park."
Det Insp Ivan Beasley from Kent Police said: "None of us will ever understand what compels people to cause harm to children, and it is unfortunately true to say that Eli suffered more than most and was robbed of his life before it had barely begun.
"Katherine Cox and Danny Shepherd maintained their innocence throughout but the jury saw through their lies.
"Only they know the true extent of the abuse Eli was put through, which is simply unthinkable to most members of society including parents who would do anything to protect their children from harm."
Libby Clark, from the Crown Prosecution Service, said: "Our case was that either Danny Shepherd or Katherine Cox had caused Eli's injuries and the death, or were aware that there was a significant risk of serious physical harm being caused to him, and failed to take reasonable steps to prevent this.
"The fatal injury and older fractures identified by one of the medical experts showed very significant similarities.
"This considerably undermined the defence case that they were caused by another person."