A MAN has admitted he killed a schoolboy whose death remained a mystery for 23 years – but denied a charge of murder.

The body of Simon Martin, 14, was found in a derelict building in Sunderland in 1990.

Now Steven Grieveson has denied murdering Simon but accepts he was responsible for the teenager’s death.

During a hearing at Newcastle Crown Court yesterday, Grieveson pleaded not guilty to a charge of murder.

Appearing on a TV screen wearing a black and white tracksuit top, he spoke only to say “not guilty” to the allegation of murder.

But the court heard through his legal team that the 42-year-old has admitted he did actually kill the schoolboy.

Brian Hegarty, defending, told the hearing: “Mr Grieveson will not dispute that he is responsible for the death.”

Judge James Goss QC told the court: “That does not mean he is admitting murder, he is admitting unlawful killing.”

The court heard a trial will take place in June to determine whether Grieveson is guilty of murder or manslaughter. No manslaughter charge was put to the defendant.

The court also heard that the issues at trial may be diminished responsibility and/or a lack of intent.

Prosecutor William Lowe QC told the court: “The crown’s allegation is he murdered Simon Martin, he is admitting unlawfully having killed him.”

Grieveson was remanded in custody and will appear at court for a further hearing in March.

Simon, who lived at Amy Street, Sunderland, had suffered head injuries.

His body was found at Gillside House, Roker, Sunderland, which has since been demolished.