At the trial, Mrs Justice Jefford told Cardiff Crown Court that the attack on the “defenceless” schoolboy, who weighed 3st 1lb (20kg), was “nothing short of horrifying”.
Logan’s body was found partially submerged in the River Ogmore, just 250m from his home in Sarn, Bridgend county in July 2021.
Rejecting Williamson’s version of events that Cole and Mulligan attacked Logan two days before his body was found and that she had run out of the house in an attempt to get help, Jefford said: “That was made up after the event to protect yourself and shift the blame.
“You had an opportunity to protect your son from further injury and you did nothing.
Logan, a previously “smiling, cheerful little boy”, died after suffering a “brutal and sustained” attack at home, leaving him with 56 “catastrophic” injuries, including extensive bruising to the back of his head and tears in his liver and bowel.
