Carlita Kilpatrick and Bernard Kilpatrick, who now live in Texas with Kwame Kilpatrick, must answer questions under oath from lawyers Norman Yatooma and Robert Zawideh, who represent Tamara Greene's family.
In a closed-door hearing Tuesday, Judge Gerald Rosen also said the lawyers can depose Jerry Oliver, Detroit's police chief during Kilpatrick's administration, the Detroit Free Press reported Wednesday.
The family's lawsuit charges the former mayor and others in his administration thwarted an investigation into Green's unsolved fatal shooting.
The lawyers want to question Carlita Kilpatrick and Bernard Kilpatrick about a rumored 2002 party at the mayoral mansion in which Carlita Kilpatrick allegedly assaulted Greene, a stripper who went by the name of Strawberry.
Kwame Kilpatrick and others in his administration publicly have denied the party and the assault occurred.
Citing the ongoing homicide investigation, Rosen has sealed many of the filings in the lawsuit and has not ruled out sealing the pending depositions.