Police have made a public appeal for Biryukova's cooperation, and have also asked the public to help.
Biryukova's attorney declined requests for comment to ABC News.
Biryukova and her husband have been locked in a difficult custody battle, during which both sides have accused the other of hurting the children, according to The Associated Press.
The AP also reported that divorce papers say Biryukova had "severe" obsessive-compulsive disorder accompanied by 10-hour cleaning binges during which she would neglect her children.
A doctor, however, testified that she was still able to care for her children.
Biryukova, however, is not permitted to have contact with her daughter who will remain in foster care until the next hearing on Dec. 5.
The couple's troubled history includes a citation for leaving Sky alone in a parked car at a Target parking lot in 2009, and angry accusations hurled at each other during their divorce proceedings.