A teenage boy testified on Tuesday that Michael Jackson told him and his brother, who has accused the pop star of sex abuse, to keep their activities at Mr Jackson's ranch secret "even if they put a gun to your head".

But during cross-examination, Mr Jackson's lead defence attorney accused the 14-year-old boy of lying, breaking into the singer's suitcase full of adult magazines and wine cellar and "snooping" around his bedroom.

The testimony of the boy, who told jurors on Monday that he saw Mr Jackson masturbating while groping his sleeping brother, is at the heart of the child molestation trial. He has also said that Mr Jackson showed the boys pornography.

"One time me and my brother and (another boy) were sitting on the bed and (Michael) told us not to tell anyone what happened, even if they put a gun to your head," the boy said in response to questions from Santa Barbara County District Attorney Tom Sneddon.

He said Mr Jackson once made a similar remark about their older sister, who has also testified at the trial.

"He told us not to tell her anything, he was afraid she might tell our mom what we were doing," the boy said. Asked by Mr Sneddon what Mr Jackson was referring to, the boy said "drinking".

Mr Jackson, 46, is charged with molesting the boy's older brother, then 13, plying him with alcohol in order to abuse him and conspiring to commit child abduction, extortion and false imprisonment. Mr Jackson, who has pleaded innocent, faces more than two decades in prison if he is convicted on all 10 criminal counts.

On cross-examination, lead defence attorney Tom Mesereau hammered at the boy's testimony that he twice stumbled on Mr Jackson groping his sleeping brother. He said he witnessed both incidents while climbing a stairway leading to the pop star's bedroom in February or March of 2003.

The boy agreed with Mr Mesereau that a bell sounds in a hallway whenever visitors approach Mr Jackson's bedroom door. But he refused to concede that Mr Jackson would have heard the alarm, saying that it was only audible from the bed area if a second door was open.

Mr Mesereau also hammered at what he said were inconsistencies in the boy's account, saying that his testimony about the two incidents conflicted with what he had previously told a psychologist.

The attorney also pointed out that a copy of the adult magazine Barely Legal, presented by prosecutors as among those that Mr Jackson showed the boy, was dated August of 2003 - six months after the family left Jackson's Neverland Valley Ranch for the last time. The boy said he never claimed to have seen that issue.

Mr Mesereau also called on the boy to admit that he and his brother had been caught breaking into Mr Jackson's wine cellar, bedroom, and stash of adult magazines - in keeping with a defence theory that they ran wild at Neverland.

"You went snooping around the entire bedroom area when Mr Jackson wasn't even there, didn't you?" Mr Mesereau asked. The boy responded: "No."

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