Judge denies Redstone granddaughter's bid to join competency suit

By Lisa Richwine

LOS ANGELES (Reuters) - A California judge on Wednesday rejected a bid by Sumner Redstone's granddaughter to join the media mogul's former girlfriend in a lawsuit that challenges the 92-year-old billionaire's mental competency.

The granddaughter, Keryn Redstone, argued in court papers that Sumner Redstone had become a "prisoner in his own home" after the former girlfriend, Manuela Herzer, was ejected from his mansion in October. Herzer, 51, had sued to be reinstated as his designated healthcare agent. Keryn Redstone had asked to be added to the case as a co-petitioner.

In ruling on the 34-year-old granddaughter's request, Los Angeles Superior Court Judge David Cowan said, “The court doesn’t believe ... her being a party truly adds anything to this case."

Cowan said that Keryn Redstone can testify as a witness in the trial if Herzer calls her.

Redstone controls a majority of the voting stock at Viacom Inc and CBS Corp. Shareholders have closely followed the case for what it could reveal about his mental condition.

Also on Wednesday, Herzer withdrew a request for a neurologist she had hired to examine Sumner Redstone. The move came after the mogul's lawyers said they would not call their own neurological expert as a witness.

Redstone's attorneys say he was fully aware of his actions when he removed Herzer as his designated healthcare agent last October. Herzer argues that he lacked the mental capacity to make that decision.

Both sides have discussed a possible settlement but have so far failed to reach an agreement. The case is scheduled to go to trial on May 6.

(Reporting by Lisa Richwine; Editing by Jonathan Oatis)