Conversation so far:
Where was Black Dahlia discovered?
Elizabeth Short's body was found in Leimert Park, Los Angeles.
Who discovered Black Dahlia's body?
Local resident Betty Bersinger discovered the body at approximately 10 a.m.
What was the date of discovery of Black Dahlia's body?
On the morning of January 15, 1947, Elizabeth Short's body was found.

Question: Do they know how long she had been there before she was found?
Self-contained rewrite: Do the authorities know how long Black Dahlia's body had been in Leimert Park before she was found?