A sobbing Britney Spears lashed out at her father Wednesday for the second time in less than a month, saying in a court hearing that she wants him out as the co-conservator of her estate and charged with abuse.

"I want to press charges against my father today," Spears told the court by phone, breaking down in tears at times. "I want an investigation into my dad."

Her comments Wednesday follow a hearing last month in which she told Los Angeles County Superior Court Judge Brenda Penny that her conservatorship is "abusive" and she wanted to choose her own attorney to help her bring the nearly 13-year arrangement to an end.

Samuel D. Ingham had been Spears' court-appointed attorney since the beginning of her conservatorship in 2008.

He submitted his petition to resign last week after the singer criticized his representation. The judge accepted Ingham's resignation Wednesday, along with the resignation of Bessemer Trust, a wealth management firm that had been appointed co-conservator of the singer's estate.

Spears has retained former federal prosecutor Mathew Rosengart, a veteran entertainment litigator who was in attendance at Wednesday's hearing, to be her new counsel.

Attorney for her father says he's not stepping down

Spears initially asked for the courtroom to be cleared before she changed her mind and spoke for about 20 minutes.

In the series of new bombshell allegations, Spears called the conservatorship "f-----g cruelty," describing severe limitations she is living under, like not being able to have a cup of coffee.

"If this isn't abuse, I don't know what is," the singer said. "I thought they were trying to kill me."

Spears told the court she was not willing to be evaluated to remove her father from the conservatorship, saying she has "serious abandonment issues." Her father, Jamie Spears, remains co-conservator of her estate, while Jodi Montgomery is conservator of Spears' person.

Speaking publicly on the singer's behalf for the first time, Rosengart urged Jamie Spears to voluntarily step down conservator.

"It is in best interest of the conservatee," Rosengart, a former federal prosecutor and veteran entertainment litigator, said outside court. "We will be moving promptly and aggressively for his removal. The question remains, why is he involved? He should step down voluntarily because that's what's in the best interest of the conservatee."

Vivian Thoreen, an attorney for Jamie Spears, said in court he would not resign.

Rosengart praised the pop star's "courage, passion, and humanity" in speaking out, calling her testimony "clear, lucid, powerful and compelling."

He said he plans to take a deeper look into what has transpired under the conservatorship.

"My firm and I will be taking a top to bottom look at what's happened over the past decade," Rosengart said.

Other key figures have distanced themselves

Since her testimony last month where Spears said she has felt forced to perform, take medication and use birth control against her will, many of the key figures who managed her affairs under the complex conservatorship setup have distanced themselves.

In addition to Ingham and Bessemer Trust, her longtime manager, Larry Rudolph, also resigned, citing Spears' desire to retire.

Spears' mother, Lynne Spears, and the American Civil Liberties Union filed court briefs in support of her desire to select her own lawyer.

Other petitions in the case, including a request by Montgomery for additional security support, were continued.

Interest in Spears' legal battle has grown since the February release of the documentary "Framing Britney Spears," which explores the singer's career and conservatorship.

Spears' fight has drawn widespread support from other artists, including Madonna, Mariah Carey and Christina Aguilera.

Fans have launched the free Britney movement, which has included a bipartisan effort from lawmakers. Sen. Elizabeth Warren, a Democrat from Massachusetts, and Sen. Ted Cruz, a Republican from Texas, have expressed their support for Spears.

On Wednesday night, Spears tweeted her appreciation for her fans and new representation. The video she posted, she said, was her "celebrating by horseback riding and doing cartwheels today."

text by Chloe Melas and Faith Karimi, CNN