A statement released to CelebTV.com reads in part, "It saddens us to confirm media reports that we have terminated our professional relationship with Britney Spears. We have represented Britney for the past month. We believe Britney is enormously talented, and has made a terrific record. But current circumstances have prevented us from properly doing our job."
Spears hired Jeff Kwatinetz of The Firm in August to help revive her flagging career.
News of the manager's departure followed stories about an investigation into an alleged contract hit against Spears' ex-husband and an attempt by a former bodyguard to give testimony at a custody hearing regarding the pop star's two sons.
Authorities said Monday that police conducted an investigation into the possible threat against Federline earlier this year, but closed the case because of insufficient evidence.
The Los Angeles Police Department probed the allegations in June, but later determined there was not enough information to keep the investigation active, LAPD spokeswoman Norma Eisenman said in response to inquiries following a report by "Entertainment Tonight" on the show's Web site that cited unidentified sources.
"There is no current investigation," Eisenman said.
The Los Angeles field office of the FBI received "nonspecific, uncorroborated allegations regarding a threat against Mr. Federline" and passed the information to the LAPD because it was not a federal matter, said FBI spokeswoman Laura Eimiller.
Eimiller declined to say when the FBI received the information and would not describe the threat.
"As a policy, I would not say that I was or was not contacted by an investigative agency," Federline's attorney, Mark Vincent Kaplan, told "Entertainment Tonight" when asked if he had been contacted by the FBI.
Gina Orr, a publicist for Spears' record label, told The ShowBuzz that she can only comment on the singer's music career. Spears does not have a personal publicist at this time, Orr said.
Meanwhile, a hearing in the Spears-Federline custody battle over their two children was held Monday, with celebrity lawyer Gloria Allred entering the fray.
Former Spears bodyguard Tony Barretto, 28, arrived to the hearing with Allred, but Family Court Commissioner Scott M. Gordon held only a brief open session before clearing the courtroom of everyone but attorneys for Spears and Federline to privately discuss unsealing documents in the ongoing case.
Barretto was employed as a bodyguard for Spears from the time that she left a rehabilitation facility in March until May 17th, 2007, Allred said in a statement.
"During that time he was in her home on a full time basis, drove Ms. Spears to various appointments and observed her behavior inside of her home, outside of her home and around her children," she said. "Our client was prepared to testify on issues of nudity by Ms. Spears, drug use, and safety issues involving the children post rehab."
Allred said Spears fired Barretto because "he didn't hear her when she asked him to pick up her hat."
The singer married Federline in October 2004. She filed for
divorce last November and the divorce became official July 30. The
two have joint custody of sons Sean Preston, 2, and Jayden James,
Spears went through episodes of bizarre behavior early this year, including attempts at a professional comeback, which took a hit last week with a sloppy performance at MTV's Video Music Awards.
Allred said that she was "shocked" that attorneys for Spears "chose not to cross-examine our client as to the substance of his declaration."
Spears had been represented by attorney Laura Wasser, but Wasser said Monday she would no longer be working for Spears. A staff member of attorney Marci Levine's office confirmed to The ShowBuzz that Levine is Spears' new counsel in the case but was unable to comment further.