A couple have been convicted over the death of their baby who died after allegedly being shaken and immersed in water.

Alistair Walker, 27, was convicted of the manslaughter of his son, while Hannah Henry, 22, was found guilty of causing or allowing the death of the three-month-old child, Ah’Kiell Walker.

Henry was cleared of manslaughter after a five-week trial at Bristol crown court but both were convicted of cruelty to a child under 16.

When paramedics arrived at the family home in Gloucester, Ah’Kiell was naked, soaking wet and so cold that his temperature could not be measured.

A CT scan showed bleeding in his eyes consistent with shaking. He died the next day. A postmortem found he had previously suffered fractures to his ribs and a shoulder.

Walker and Henry denied manslaughter, causing or allowing the death of a child and cruelty.

But the jury was told that in the weeks before his son’s death, Walker Googled: “Can I squeeze my baby?” and “Can babies feel pain?”

In a 999 call played in court, Henry sobbed as she described how her son was coughing up blood and barely breathing. Her partner could also be heard speaking in the background.

A short time later, paramedics arrived to find Ah’Kiell seriously ill. He was taking just four breaths per minute. His lungs were full of water and a paramedic tipped him up to clear the liquid. Next day, he was declared brain dead and the decision was made to remove his breathing tube.

In the witness box, Walker denied hurting his son and said he would have protected him if he was threatened. “I loved him to bits,” he told the court.

Walker claimed that on the morning he collapsed in July 2016, the baby looked pale. He said he told Henry to splash water on to his face. He alleged that one of the paramedics had caused the brain injury.

Walker was also asked in court about scratches to his son and it was put to him that he had sexually abused the child, but he denied this.

Henry said her son had been happy and she had not noticed him being in pain before his collapse. When asked what she would have done if she had believed that Ah’Kiell had been injured by Walker, she replied: “I would have phoned the police.”

She admitted that Walker “frightened” her. She said he had broken her jaw before she was pregnant with Ah’Kiell, but denied that he was violent towards the baby. However, she had sent a WhatsApp message to her mother, saying: “He’s so horrible to Ah’Kiell. Don’t know how he does it.”

Chief inspector Richard Pegler, of Gloucestershire police, described Ah’Kiell as “a beautiful baby boy”.

“This was a complex and difficult case as we don’t know precisely what happened that morning – there are only two people who do – but what we do know is that Ah’Kiell’s death was not natural or readily explained and that his injuries were indeed non-accidental,” he said.

“I would like to pay tribute to the paramedics and other medical professionals in this case who clearly did their very best for Ah’Kiell.”

The judge, Sir John Royce, told the jury that they had sat through a “harrowing” case. The pair will be sentenced on 1 June.