The American Civil Liberties Union filed a lawsuit in San Diego’s federal court today alleging that immigration officials had unnecessarily and unjustly separated an asylum-seeking woman from her then-six-year-old daughter.

The woman, who fled the Democratic Republic of the Congo with her daughter, has been held at Otay Mesa Detention Center, since the child was taken from her in early November, according to the lawsuit. They had asked for asylum at the San Ysidro port of entry on Nov. 1 and were detained for a few days together before immigration officials split them up to go to different, longer-term custody facilities.