Andrew Lloyd, 37, of Swansea, Wales, was sentenced to life in prison in 2005 after subjecting 13-month-old Aaron Gilbert to a four-week assault campaign.

Aaron’s mum Rebecca Lewis, then 21, was jailed for seven years for failing to protect her son from violent, drug-taking Lloyd

Andrew Lloyd, from Swansea, Wales, murdered his girlfriend Rebecca Lewis’s 13-month-old son, Aaron Gilbert. During his 2005 trial, it was revealed that he had tortured the boy to a four-week catalogue of brutality.

According to WalesOnline, the Jail Service has verified he died while serving his sentence in prison at the age of 37.

According to a spokesperson: “Andrew Lloyd, a prisoner in HMP Full Sutton, died in custody on November 19. The Ombudsman for Prisons and Probation has been notified.”

Lewis was found guilty by a Swansea Crown Court jury of neglecting to protect her son from the violent, drug-taking Lloyd at their house in the city’s Townhill district.

On May 5, 2005, Lloyd horribly abused the baby when he was alone with him.

He lost his cool and violently shook Aaron, causing his head to crash with a wall.

Lloyd murdered 13-month-old Aaron Gilbert after subjecting him to a four-week onslaught of cruelty. Mum Lewis had left Aaron with Lloyd when she went shopping, despite the fact that she was aware that he had assaulted him throughout weeks of abuse.

A pathologist discovered a significant brain injury and nearly 50 exterior injuries after Aaron died the next day in the hospital.

Lloyd, then 23, was convicted alongside Aaron’s mother, then 21-year-old Lewis, in December 2006 at Swansea Crown Court.

He was sentenced to a minimum of 24 years in prison, which would have made him 47 if he served his entire term.

Lewis was sentenced to seven years in prison for familial homicide and attempting to pervert the course of justice in a case that was considered a judicial landmark at the time. She was one of the first people in Wales and England to face familial homicide charges.

At the time, Swansea Crown Court heard that Lewis and Lloyd’s connection began at the end of March 2005.

Lloyd developed a dislike for baby Aaron after moving in with Lewis.

The jury heard how he yelled at him, grabbed his ears, threw bottles at him, swung him by his ankles “like someone swinging a cat by its tail,” smothered him with a blanket, and blew cannabis smoke in his face.

There was also evidence that Lloyd bit Aaron on the cheek five days before he died.

Aaron’s appearance became so disfigured as a result of being systematically and violently assaulted that a neighbor compared him to the Elephant Man.

Mr Justice Langstaff, who sentenced Lloyd at the time, said: “You murdered Aaron after subjecting him to a sustained catalogue of brutality during the last four weeks of his life.”

“I consider your actions during those four weeks to be inextricably tied to what you did on the day you inflicted the fatal injury.”

Lloyd’s case reached London’s Appeal Court in 2007, when he challenged his minimum prison term of 24 years.