Jackson’s lawyers sought to discredit the mother of the teenager who has accused the pop star of child molestation, plying the then 13-year-old with alcohol and conspiring to hold the boy and his family against their will.
The defence called Larry King to tell jurors about comments allegedly made to him by Larry Feldman, a lawyer who once represented the young accuser’s mother.
In a court session in which the jury was not present, Mr King told the judge about his conversation with Mr Feldman.
“He said she is a wacko,” Mr King testified.
“He said she is in it for the money.”
The defence maintains the alleged victim’s family made the accusations against Jackson only after meeting Mr Feldman, who previously brokered a US$20m (A$26m) settlement for a teenager who claimed the singer abused him in 1993.
But Judge Rodney Melville refused to allow the presenter’s statements on the grounds Mr King was unable to say that Mr Feldman had directly quoted the accuser’s mother.
Judge Melville also disallowed similar testimony by publisher Michael Viner about a conversation during a breakfast meeting in which Mr Feldman allegedly said the mother’s “motives were financial.”
Former prosecutor Laurie Levenson said the decisions were a major setback for Jackson’s defence.
“They would love to have had those witnesses say the mother was out for the money,” Ms Levenson told the Agence France Presse news service.
She also said it appeared increasingly unlikely Jackson would testify in his own defence.
The trial continued with the appearance of Azja Pryor.
The Hollywood casting assistant and former fiancé of US comedian Chris Rock befriended the accuser’s mother in 2000.
Ms Pryor told the court she had heard accuser’s mother praise Jackson and never once spoke of her child being molested.
In her testimony, Ms Pryor said the mother complained to her in March 2003 that two German associates of Jackson had kept the family away from the star.
The time period coincides with the February 20 to March 12, 2003 timeframe in which prosecutors allege Jackson molested the teenager.
It appears the defence may wind up its case earlier than expected, after lawyers dramatically reduced the number of witnesses they intend to call.
NBC and ABC America news services quoted sources close to the trial saying the case could be sent to the jury by the first week of June.