Britney Spears' lawyer says he is 'moving aggressively' to remove Jamie Spears as conservator

Days after Britney Spears was granted a new lawyer in her fight against her conservatorship, attorney Mathew Rosengart says he is "moving aggressively and expeditiously" to petition to remove the singer's father as co-conservator – "unless he resigns first."

Last Wednesday, Judge Brenda Penny granted Spears' request to hire Rosengart, a former federal prosecutor-turned-skilled litigator, to be her lawyer in the singer's ongoing effort to end her 13-year conservatorship, under which she has little control over her finances or important life decisions.

Spears, who dialed into the hearing, spoke for about 15 minutes and became emotional, saying she wants an "investigation" of the alleged abuse. She also reiterated that she wants her father, James "Jamie" Spears, out as a co-conservator, and that she refuses to undergo more medical assessments, which she called "stupid psych tests."

“I want to press charges for abuse," she said. "Instead of investigating my capacity, I want an investigation on my dad.”

More: Britney Spears says '#FreeBritney' after winning right to hire lawyer in conservatorship case

On Monday, Rosengart spoke to reporters outside a Los Angeles courthouse following a hearing involving co-conservator Jodi Montgomery's request for more money for enhanced security after receiving death threats. Jamie Spears has opposed this, and the two have engaged in dueling recriminations via legal documents filed in the case. A decision was delayed until the next hearing, scheduled for July 26.

While speaking to the reporters, Rosengart reiterated his firm's intent to remove Jamie Spears as co-conservator, as he already mentioned at the July 14th hearing.

Spears' new lawyer also expressed gratitude to the singer "for her courage and for her strength," and to Penny, "for her courtesy in welcoming my firm and I into this case."

"And I also want to thank Britney Spears fans and supporters," he added. "The outreach and support for my firm, myself and most importantly Britney has truly been overwhelming from coast to coast and literally throughout the world."

Spears made waves earlier this week with an emotional social media post that called out her family as she vowed not to perform "on any stages anytime soon" as long as her father remains in control of her conservatorship.

"This conservatorship killed my dreams ... so all I have is hope and hope is the only thing in this world that is very hard to kill ... yet people still try," Spears wrote Saturday in a lengthy Instagram post, adding that her "so-called support system hurt me deeply."

In addition to noting she wouldn't perform as long as her father, James "Jamie" Spears, handles "what I wear, say, do, or think," the singer seemingly took issue with her sister, Jamie Lynn Spears, performing one of Britney's songs in a tribute at the 2017 Radio Disney Music Awards.

Representatives for Britney Spears, Jamie Spears and Jamie Lynn Spears did not respond to USA TODAY's requests for comment.

Previously: Britney Spears calls out her family in emotional post: 'This conservatorship killed my dreams'

In her Instagram post, the pop icon said she would "much rather share videos" online of herself dancing in her living room than "onstage in Vegas."

"Look I'm not gonna be performing on any stages anytime soon with my dad handling what I wear, say, do, or think!!!! I've done that for the past 13 years," she wrote. "I'm not gonna put on heavy makeup and try try try on stage again and not be able to do the real deal with remixes of my songs for years and begging to put my new music in my show for MY fans ... so I quit !!!"

"Hope is all I have right now," Spears concluded, calling out those who criticized her latest dancing video in comments. "You're lucky I post anything at all ... if you don't like what you see, unfollow me !!! People try to kill hope because hope is one of the most vulnerable and fragile things there is."

This month, Spears' longtime manager, Larry Rudolph, reportedly announced his resignation in a letter to her conservators, citing the pop icon's intent to "officially retire" from music.

In January 2019, Spears abruptly suspended her Las Vegas residency because of her father's health issues. She has not performed since.

Contributing: Maria Puente and Bill Keveney

This article originally appeared on USA TODAY: Britney Spears conservatorship: Lawyer 'moving' to remove Jamie Spears