Witnesses heard a "child's fearful voice saying sorry", loud banging and a man screaming about the loss of a shoe, Woolwich Crown Court was told.
He will be sentenced on Tuesday.
The jury heard Iheanacho, of Hounslow, was in a relationship with Alex's mother Lilya Breha and would often stay in her flat in Catford.
Ms Breha nodded as the verdict was announced and quietly wept in court.
Alex suffered fatal head and stomach injuries and died in hospital two days after the attack.
One of his trainers was later found in the play area by police.
Iheanacho, who was known to Alex as "Daddy Mills", admitted beating the boy before in a note in his diary which read: "Do I really love Alex, five years old small cute lil boy.
"Who want nothing more, than daddy mills to love him protect him but most of all keep him from harm - even though I had to beat him just now for sicking up in the cab - why why why I say - so the answer is yes yes yes I love him and like with all my heart but may not enough."
Iheanacho, who denied murder, gave several different accounts of how the injuries were caused including that Alex fell off a climbing frame, which were all rejected by the jury.
Rob Davis, district crown prosecutor, CPS London Homicide, said: "Only Marvyn Iheanacho knows how Alex was fatally wounded but it is certain his anger boiled over at some point on that evening.
"His actions that day tragically ended a young boy's life and deprived a mother of her son.
"His efforts to cover up what really happened, first to Alex's mother by claiming Alex had simply fainted and hit his head, then by lying and repeatedly changing his story to police show his greatest concern was for himself."
Culled From BBC
Culled From BBC
Bastard mad man!!!
ReplyDeleteDie in jail niga.