Los Angeles, California - Britney Spears' lawyer has taken Jamie Spears to task in the wake of new allegations of intrusive and possibly illegal surveillance.

Attorney Mathew Rosengart brought down the hammer in an Los Angeles County Superior Court filing Monday after the recent release of the FX/Hulu documentary Controlling Britney Spears and a report by the New York Times published in concert with the film.

"Mr. Spears was, of course, never fit to serve, for all of the many compelling reasons already contained in the record, ranging from his lack of financial acumen, to his bankruptcy, to his reported alcoholism, to the trauma he caused his daughter since childhood, to the Domestic Violence Restraining Order recently issued against him," Rosengart wrote in a third supplement to a petition seeking removal of Jamie Spears as conservator of his daughter’s estate.

"But now, the chickens have truly come home to roost," he continued. The New York Times "reported that Mr. Spears engaged in horrifying and unconscionable invasions of his adult daughter's privacy."

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"Specifically, the Times reported that he and others 'ran an intense surveillance apparatus that monitored [Ms. Spears'] communications' and also evidently captured attorney-client communications with her prior lawyer... a sacrosanct part of the legal system."

Jamie Spears' attorney, Vivian Thoreen, did not respond immediately to a Los Angeles Times request for comment.

Controlling Britney Spears sourced its information from Alex Vlasov, a former employee at Black Box Security, Felicia Culotta, the singer's friend and assistant, and Tish Yates, who was head of wardrobe for several of Britney’s tours during the conservatorship and said she had a close relationship with her.

Among the allegations are that Britney Spears' security team functioned more like prison guards.

Security team members were also allegedly given prepackaged envelopes of medication that they then forced Spears to take.

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What's more, all of Britney's movements were supposedly documented in group texts that included Edan Yemini, the head of Black Box Security, Robin Greenhill of Tri Star Sports and Entertainment Group, which handled the singer's business affairs, and Jamie Spears. Her phone activity was allegedly monitored using a mirrored iPad.

Another shocking accusation is of an audio recording device being placed in Britney's bedroom, which captured hundreds of hours of private interactions.

The star's spending was apparently so tightly regulated that she had to sneak sushi and a pair of Skechers.

There are also claims that Jamie Spears allegedly tried to create a rift between Britney and Felicia Culotta, and that Black Box allegedly investigated the #FreeBritney movement.

Vlasov (30) was an executive assistant and operations and cybersecurity manager for Black Box, which was hired by Jamie Spears to look out for his daughter.

In his nine years at the firm, Vlasov told the New York Times, he was "the only person at Black Box that knew everything, really," due to his position close to the company's founder.

His recollection of events was backed up by others involved with the conservatorship who wanted to stay anonymous, according to the New York Times. Vlasov provided emails, text messages and audio recordings to support his allegations.

Jamie Spears said in a filing on August 12 that he was planning to step down as the conservator of his daughter's finances, despite claiming there was no legal reason for his removal, but offered no timetable.

He said he needed to hang around to handle several accounting issues and accused Rosengart of moving on Britney's behalf "precipitously, without adequate investigation, and based on unsubstantiated allegations and improper opinions."

He also questioned whether changing conservators at this point would be in the singer's best interests. Then, on September 7, reversing course, he filed a petition to end the 13-year conservatorship.

"As Mr. Spears has said again and again, all he wants is what is best for his daughter," that document said. "If Ms. Spears wants to terminate the conservatorship and believes that she can handle her own life, Mr. Spears believes that she should get that chance."

Jamie Spears served as conservator of Britney Spears' person and her estate until he was replaced as conservator of her person in 2019.

Rosengart shot back at Jamie Spears in Monday's filing, which was obtained by the LA Times.

"Mr. Spears has crossed unfathomable lines. While they are not evidence, the allegations warrant serious investigation," he wrote, noting that California is a two-party consent state with regard to recording private communications.

He mocked Jamie Spears' contention that there was no legal reason to remove him as conservator as "legally and factually preposterous."

"Mr. Spears's latest efforts at delay must be rejected; he must be suspended on September 29th; followed by the prompt termination of the conservatorship," the filing said.

The court will hold its next hearing on the conservatorship Wednesday in downtown Los Angeles.