UPDATED: Lawyers for Sumner Redstone are prepared to launch a fierce attack on the credibility of the one-time girlfriend who has gone to court to question his mental competency. The Redstone team plans to paint Manuela Herzer as a money-grubbing schemer, who lied to the billionaire media magnate, and encouraged members of his staff to lie, to protect her own interests and to keep Redstone away from the family and friends who really cared about him, according to a trial brief filed Thursday in Los Angeles.

Redstone discovered Herzer’s pattern of lies last October — including her efforts to keep one of his girlfriends from visiting him at his Beverly Park home — and quickly moved to force Herzer out of his home, according to the legal document. “He made that decision based upon Ms. Herzer’s undisputed dishonesty,” the document says. “She deceived him, he found out about it, and he threw her out of the house. Period.”

The filing with fresh details about the Redstone-Herzer falling out came just before a final hearing Thursday into the boundaries of testimony in a trial set to begin Friday before Judge David J. Cowan. The case centers on a claim by Herzer, 52, that Redstone’s lawyers and staff conspired to throw her out of the magnate’s home in October and, four days later, to remove her as his health care agent. Herzer claims that the billionaire’s care suffered as a result. Her lawsuit demands she be reinstated as the person overseeing Redstone’s well being.

“The trial will expose the tragic inconvenient truth that Sumner Redstone needs the court’s protection from those who have lied to and exploited him in his debilitated condition,” said Herzer’s lead lawyer, Pierce O’Donnell, in a statement. “We look forward to trial.”

Herzer’s legal team previously argued that Herzer’s behavior should not be a subject of the trial, which they said should focus only on Redstone’s mental state and the reasons behind his alteration of his advance health care directive.

Lawyers for the man who holds a controlling interest in both CBS Corp. and Viacom consistently have contended that Herzer — a one-time girlfriend and frequent companion of Redstone over nearly 20 years — has been motivated by her desire to continue to profit financially from the relationship. Thursday’s brief added new fodder to that argument.

The legal claim says that Herzer and another former Redstone girlfriend, Sydney Holland, received “some $150 million” from him between 2010 and 2015, when he forced both out of his life. The duo also “were named beneficiaries of his trust and exercised virtually unfettered authority over his finances,” Redstone’s papers say.

But the two women knew that they stood to lose another pot of money — Herzer was in line to get $50 million and a $20 million home from Redstone’s estate — after he discovered their duplicity and removed them from his estate, Redstone’s lawyers allege.

The new legal filing depicts Herzer as rushing about L.A., spending piles of Redstone’s money, in the days before he finally caught on to her and had his staff remove her from his home. Between late August and Oct. 12 of last year, when she was banished, Herzer ran up more than $365,000 in credit card charges, the filing contends. She had $40,000 in cash delivered to his mansion 11 days before she was forced out and, a day later, executed a $5 million grant agreement with Redstone to benefit her foundation, the filing says.

Such high-flying behavior was “far from” Herzer’s own depiction of herself as “sitting by Mr. Redstone’s side worried about his health,” the legal brief says. Among the big ticket forays by Herzer in the days before she was asked to leave — $57,000 at an interior design store, $3,700 at a West Hollywood boutique and $7,300 at Barneys.

The falling out between Redstone and his long-time companion came to a head on Oct. 10, when Terry Holbrook, a woman who visited him frequently in his home, told Redstone that she had been regularly available to come to see him, even though Herzer had told him otherwise. Redstone’s nurses had also been instructed by Herzer to lie about Holbrook’s availability, the trial brief contends.

When Redstone learned this his “reaction was angry and decisive.” Two days later, “Mr Redstone threw Ms Herzer out of his house (and life)  . . . and thereafter revised his estate planning documents, including his advance health care directive.” He ordered that money that would have gone to Herzer from his estate instead go to his charitable foundation.

The changes to his estate and health plans were witnessed not only by one of this attorneys but by Dr. James Spar, a geriatric psychiatrist who is prepared to testify that Redstone was of sound mind when he made the changes, the trial brief says.