Generate a correct and concise answer for the question based on the words in the context.

Context : Margie Velma Barfield (nee Margie Velma Bullard) (October 29, 1932 -- November 2, 1984) was an American serial killer, convicted of one murder, but she eventually confessed to six murders.
Question : Which crime led to the conviction of Velma Barfield?
murder