I think the following is the case you are referring to:
Deposition made in the Suit of Morrier vs. Molley Moore, Prince Edward County, Virginia 1814
"Jemimah Walthall of lawful age dopseth and saith that fro many years she lived near Neighbor to Robert Evans (Father to Molly Moore) tha she was well acquainted with a Woman in the possession of sd Evans by the name of Tabb who had long black hair & of a reddish complexion & who was always said to be of Indian extraction, that the said Tabb had seven children namely Moreer, Sam, Bridget, Amey, Jemmy, Phebe and Rachel - she further saith that after the death of sd Robt Evans, Moreer and her two children by the nmes of Douglas and Tyler was possessed by Molly Moore (then Evans), Sam and Bridget by Robert Evans, Jr., the aforesd Bridget fell to John Tucker by Marriage since which time sd Bridget has obtained her freedom in the superior court of Prince George County and the sd Bridget was always called Sister to Moreer and both Daughters of aforsd Tabb who was the only Breeding coloured Woman that lived in the Plantation of Robert Evans. and further this Deponant saith not." Jemimah (+) Walthall
[Carolyn Goudie distributed this at one of the AAH&GS meetings].