Conversation so far:
When did Black Dahlia move to California?
In December, at age 18, Elizabeth Short relocated to Vallejo to live with her father.
Why did Black Dahlia move to California?
Elizabeth Short's mother received a letter from her presumed-deceased husband, which revealed that he had started a new life in California. Short relocated to live with her father.

Question: How did he fake his death?
Self-contained rewrite: How did Black Dahlia's father fake his death?