His former teacher told an Old Bailey jury how James Watson made copies of a front-page story about Rikki Neave’s death.
Watson, now aged 40, of no fixed address, has denied murder and the trial at the Old Bailey continues.
David Benjamin, who was head of house at Walton school in Peterborough, said Watson did not attend on November 28 1994, the day Rikki disappeared.
On November 30 1994, he returned for his first full day in school "for ages", the witness said.
That afternoon, he allegedly went out to get the local evening paper featuring Rikki on the front page.
Watson then showed him one of six copies of the front page he had made, saying they were to display in the children's home where he was staying in nearby March, jurors heard.
Mr Price asked: "Were further copies of the document made by James?"
Mr Benjamin replied: "Yes. 25 of them."
Watson allegedly went on to tell his teacher: "This is my mate's brother and I knew him."
Rikki was found strangled and posed naked in a star shape in woods near his home, the Old Bailey has heard.
More than 20 years later, DNA belonging to 13-year-old James Watson was found on Rikki's clothes which were dumped in a wheelie bin.
The jury also heard that the late stepfather of murdered Rikki Neave had described the youngster's turbulent home life in evidence to court from beyond the grave.
Dean Neave was not living with Rikki's mother Ruth at the time he went missing in Peterborough on November 28 1994.
On Thursday, jurors in Watson's murder trial heard evidence from Ms Neave's late ex-husband, who died in a car crash in 1999.
Prosecutor John Price QC read out a statement Mr Neave made to police in December 1994.
Mrs Justice McGowan told jurors: "In respect of this witness, if he was still alive the defence would have wanted to cross-examine him and ask him some questions."
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