A five-year-old boy was battered to death in a park by his mother's boyfriend, who flew into a rage after the child lost one of his trainers, a court heard.
Marvyn Iheanacho (39) is accused of causing Alex Malcolm fatal head and stomach injuries during a violent assault.
Witnesses heard a "child's fearful voice saying 'sorry'", loud banging, and a man screaming about the loss of a shoe, jurors were told. Prosecutors say the banging could have been from "repeated assaults" on Alex in Mountsfield Park, Catford, south-east London.
Mr Iheanacho, from Hounslow, west London, is standing trial at Woolwich Crown Court, where he denies murder.
"The prosecution say that he died at the hands of this defendant, a man who was looking after him, acting as his stepfather, but who on the afternoon/early evening of November 20 last year lost his temper and violently assaulted the boy, causing him fatal head and stomach injures," said prosecutor Eleanor Laws QC.
The jury heard he was in a relationship with Alex's mother Lilya Breha and would often stay at her flat in Catford.
CCTV captured Mr Iheanacho taking Alex from his home, on three separate buses, to the park, where they arrived at around 5.12pm, when it was already dark.
Ms Laws said there were no witnesses or CCTV footage of "the defendant landing blows on Alex", but added: "There is, however, clear evidence as to the fact the defendant lost his temper with Alex before he sustained his injuries."
The trial continues.