Theodora Kracaw Kroeber Quinn (March 24, 1897 – July 4, 1979) was a writer and anthropologist, best known for her accounts of Ishi, the last member of the Yahi tribe of California, and for her retelling of traditional narratives from several Native Californian cultures.
Theodora Quinn knows a lot of information on the Yahi tribe of California. 
This could be true, but we do not know for sure. 