The father of a five-year-old boy murdered by his mother, stepfather and stepbrother has said he wakes up screaming when his son visits him in his dreams.

Logan Mwangi was found dead in the River Ogmore on the morning of 31 July 2021, just a few hundred metres from the flat where he lived in Bridgend, south Wales.

The youngster, dressed in mismatched pyjamas, had suffered 56 injuries, some of which were “catastrophic” and likened to those found on victims of high-speed crashes or a fall from a height.

His mother Angharad Williamson, 31, stepfather John Cole, 40, and 14-year-old stepbrother Craig Mulligan were sentenced for his murder on Thursday.

Logan’s biological father Ben Mwangi said he collapsed at work when police told him his son’s body had been found dumped in the river near his home.

In a victim impact statement read out on his behalf in court, Mr Mwangi said: “I couldn’t believe what I was hearing, I felt so confused. I just collapsed on the floor and hit my head.

"I just felt like every fibre in my body had died and couldn’t stop crying.

"I couldn’t understand how something like this could have happened to my son.

"The rest of the day was a blur as I waited for more information. It was so painful."

Mr Mwangi said he was devastated he was not there to protect his son, whom he described as “the sweetest and most beautiful boy”.

Evidence heard in court suggested Logan could have been saved if an ambulance had been called.

"The last 10 months have been hell for me,” the father said. "I can’t sleep and keep experiencing recurring nightmares.

"My dreams of Logan are so vivid. Logan comes to me to tell me he’s OK and to check that I’m OK.

“He runs into my arms and I hold him tight, but he then slowly disappears. I wake up screaming and crying.”

Logan’s mother Williamson was told she would spend at least 28 years behind bars for his murder, while her boyfriend Cole will serve a minimum of 28 years in jail.

Mulligan - Cole’s stepson from a previous relationship - was detained for a minimum of 15 years after also being found guilty of Logan’s murder.

A trial at Cardiff Crown Court heard how Williamson reported Logan missing at 5.45am on 31 July 2021 and accused a woman, against whom she held a grudge, of abducting him.

Logan, previously a “smiling, cheerful little boy”, was discovered in the River Ogmore in Pandy Park that same morning.

Police found him partially submerged, wearing dinosaur pyjama bottoms and a Spider-Man top just 250 metres from his home. He was later confirmed dead in hospital.

CCTV footage shown to the jury during the trial captured Cole and the teenage boy, who was 13 years old at the time, leaving the family’s address in the early hours of 31 July.

Cole was carrying something in his arms towards the river that he later confirmed was Logan’s dead body.

Experts said Logan’s injuries could have been caused only by a “brutal and sustained assault” inflicted in the hours or days prior to his death. They also said the injuries were “consistent with child abuse”.

In the months and weeks leading up to his death, Logan had been “dehumanised” by his family, prosecutors said.

His stammer is said to have worsened, becoming particularly bad around Cole. He wet himself more frequently and began self-harming.

Friends of the couple said Cole told them he did not like Logan, and others said his attitude changed after he became obsessed with the idea Williamson had cheated with Logan’s father.

After Williamson gave birth to his child, Cole was reluctant to let Logan see the baby and later claimed the boy had tried to smother the infant.

Medics made a safeguarding referral to the police after Logan suffered a broken arm in August 2020, with Williamson saying he had fallen down the stairs.

She took him to hospital the day after the incident and said she thought he had only dislocated his shoulder and had tried to put it back.

Later she told a friend Mulligan had confessed to pushing Logan down the stairs, but it was not until January last year that she told the police.

Additional reporting by Press Association