Violence inflicted on a teenager accused of being a witch was "wild" and "completely feral", a witchcraft expert has told the Old Bailey.
Kristy Bamu, 15, drowned in a bath in his sister's east London flat after he was was beaten and tortured in 2010.
Magalie Bamu and Eric Bikubi, both aged 28 and from Newham, deny murder.
Expert Dr Richard Hoskins said the attack went way beyond accepted practices in Democratic Republic of Congo, where the family originate from.
He told the jury: "In this case the evidence that I've read is something completely feral, it's wild, it's completely out of control. It's beyond the normal patterns that exist in the Congo."
Ms Bamu and her boyfriend Mr Bikubi are accused of murdering Kristy on Christmas Day because they thought he was affected by an "evil force called kindoki".
Dr Hoskins told the court that Kristy wetting himself could have been the trigger for the alleged violence.
"The trigger that needs to occur for people to think someone is possessed by kindoki can be anything out of the ordinary. Bed-wetting is a classic example of this."
He added that other factors could have been Kristy's older brother Yves' autism, an allergic reaction that made Yves' lip swell or a younger sibling having problems getting out of bed.
Dr Hoskins said it was believed that the malevolent power could possess someone, and that they could use it to control other people.
He added that over the last 15 years the "child witch phenomenon" has emerged where children were accused of being possessed. He said belief in kindoki was "all pervasive" in Congolese society regardless of someone's standard of education or social class.
"It's absolutely standard regrettably to accuse a child in the DRC of having witchcraft... nobody would raise an eyebrow at the suggestion in the DRC."
Mr Bikubi has admitted manslaughter on the grounds of diminished responsibility, as well as two charges of causing actual bodily harm to Kristy's siblings.
Ms Bamu denies murder and two charges of causing actual bodily harm.
The trial continues.