The pop singer previously was cross-examined for only 14 minutes
Credit: INF; Martin Fried/UPI Photo/Landov

Britney Spears spent more than two hours at the Los Angeles office of Kevin Federline‘s lawyer, Mark Vincent Kaplan, Monday for an ongoing deposition in the ex-couple s custody battle.

At 10:40 a.m., Spears, 26, wearing a dark blue top and jeans, drove up to the office in her white Mercedes-Benz SL65 with friend Sam Lutfi. Both had serious expressions on their faces. The singer was spotted leaving at 1:20 p.m.

The singer has missed numerous appointments for the court-ordered cross examination. She was expected to be grilled about her past drug and alcohol use, her apparent failure to follow court orders and other matters pertaining to her parenting skills.

Federline’s attorney will use evidence gathered in depositions to try to convince a court that his client should retain primary physical custody of the ex-couple’s children. A custody trial is set for April.

“Kevin wants nothing more than to be able to parent his children with participation by their mother,” Kaplan previously told PEOPLE. “But the best interest of the children require that they be in the most sound, safe, nurturing and consistent environment. That is paramount.”

On Jan. 3, Spears was deposed for only 14 minutes, after arriving one-and-a-half hours late. That night and into the next morning Spears had a four-hour standoff with police, ending with her brief hospitalization.

Last Monday, the singer lost all visitation rights to sons Preston, 2, and Jayden 1, indefinitely after she showed up for a hearing, then left without entering the courthouse.

Reporting by Pernilla Cedenheim