A boy accused of murdering Damilola Taylor could not have attacked the 10-year-old because he was elsewhere at the time, the Old Bailey has been told.
Damilola had only been in Britain three months when he was killed
The youth, then 12, was under 24-hour curfew at a children's home more than a mile away, the defence said.
A log at the home showed he had been to a shop returning later with a worker, shortly before Damilola was stabbed.
He and his brother, 18, who cannot be named, deny murder in 2000, along with Hassan Jihad, 20.
Home worker Sharon Nedrick told the court: "I don't recall them leaving but I recall them returning."
Damilola was found in a stairwell of a block of flats in Peckham - more over a mile away from the home.
Orlando Powell QC, defending, said he would be calling four witnesses from the home to prove his client's innocence.
He described the boy as a "wretched nuisance" at the time of the offence but said a criminal trial was not a "popularity contest" and the jury did not have to like the defendant to find him not guilty.
The trial continues.