The teenager accused of murdering Rhys Jones was caught by a listening bug trying to persuade a key witness to change her story to support his alibi, a jury at Liverpool Crown Court was told today.

Sean Mercer, 18, allegedly told the grandmother of one of his co-defendants that she should tell the "bizzies", the police, that she had not seen him just after the 11-year-old schoolboy was shot.

But she refused to say she saw him on Tuesday rather than Wednesday, the day of the shooting, because that would be lying, she said, and she was not prepared to do so.

The jury listened to a series of graphic exchanges recorded on the listening device secretly planted in her daughter's home allegedly between the elderly witness, Mercer and her grandson identified only as Boy M.

On one recording, the grandmother can be heard saying: "I said to Mercer, if you haven't done it you've got nothing to worry about. I dunno what this lying's about.

"He went 'I know, I know' but he went white."

The prosecution suggest that Mr Mercer raced to Boy M's home in Croxteth, east Liverpool, immediately after he shot Rhys outside The Fir Tree public house in August last year.

Boy M's grandmother, who gave her evidence from behind a screen, told the jury that Mr Mercer had arrived at the front door that evening, left the bicycle in the hallway and went upstairs to see her grandson.

They were joined shortly after by James Yates, 20, and Nathan Quinn, 18, both co-defendants, who stayed for around 10 minutes before leaving in a khaki-coloured people carrier with Mercer, leaving his bicycle behind. The prosecution say they then set about destroying the evidence.

On another recording, dated September 3, almost two weeks after the murder, the grandmother is heard calling up to her grandson "it's Mercer again" followed by the sound of footsteps on the stairs.

The witness is heard saying: "I can't....I can't change my statement. I'm not lying".

A male alleged to be Mercer then says: "Said you were at (the home of Boy K, another co-defendant) ". "No, I'm not lying", insists the witness.

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