Britney Spears' former bodyguard accused the pop star of having "issues of nudity and drug use" since she returned from rehab.

The bodyguard, Tony Barretto, filed a declaration in the custody battle which alleges "nudity, drug use and safety issues post-rehab."

The bodyguard has been described as a "secret witness" against Spears in her custody battle with Federline.

Barretto also shed light on reports of a planned "hit" on Britney's ex-husband Kevin Federline emerged.

The bodyguard's attorney, the high-profile Los Angeles lawyer Gloria Allred, said in a press conference Monday that Barretto was prepared to testify under oath Monday but Spears' attorney chose not to cross-examine the bodyguard. She said his declaration went "unrefuted and unchallenged."

Barretto started working for Britney when she got out of rehab, and was fired on May 17.

Barretto said, while working for Britney, he became "very concerned" about the safety of her two boys.

Meanwhile, FBI and LAPD are investigating legitimate leads on a contract hit on Spears' ex-husband Federline's life. FBI made attempts to contact Federline to inform him of the potential danger, "ET" reported.

Spears 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, who turned 2 on Friday, and Jayden James, who turned 1 on Wednesday. Federline reportedly has been fighting to get full custody of the two boys.

Britney Spears made a disastrous start to her career revival last week in her opening act at the MTV Video Awards, which was followed by more purported photos of her without underwear hitting the Internet.

Britney Spears has an album due in stores on Nov. 13.