An unemployed man left to look after his girlfriend's 14-month-old child "battered" the boy causing him horrific internal injuries, Birmingham Crown Court heard.
Cameron Rose was rushed to Heartlands Hospital but died despite all efforts to save him.
Nicholas Kirnon (22), has denied murdering the toddler while Sarah-Louise Rose has pleaded not guilty to a charge of manslaughter and allowing the death of a child.
James Burbidge QC prosecuting yesterday said Rose, who had two children, including Cameron, formed a relationship with Kirnon in about January last year and they lived at a flat in Kempson Road, Bromford.
He said she worked at Ladbrokes in Birmingham four days a week as a cashier and that she had paid her boyfriend to look after her children.
As a result, he said, during the day Kirnon was left in charge of them and was responsible for feeding the youngsters and changing Cameron's nappy.
On May 10 last year, said Mr Burbidge, Rose had left for work and according to Kirnon Cameron had been crying.
He was to tell the police that he had left Cameron on a settee, heard a cry and found he had fallen off.
Kirnon said that the boy was drowsy and weak and that he decided to take the child to his mother's home so she could see for herself. "In fact we say that he had battered the child and was now attempting to cover up for what he had done," said Mr Burbidge.
He said on arriving at the mother's home in Castle Vale Cameron was barely breathing and an ambulance was called.
At Heartlands Hospital, said Mr Burbidge, it was discovered Cameron had extensive bruising, especially to his stomach, and a post mortem examination revealed he had died from significant injuries to his internal organs, especially to his bowel and liver.
The case continues.