The key elements include the figure of Sweeney Todd as a barber who committed heinous murders. There were rumors about his killings in London in the 19th century. Another important part is the connection to Mrs. Lovett and her making meat pies from the victims. These elements combined create the dark and disturbing story that has been passed down and fictionalized over time. There were likely real - life factors like poverty, crime, and desperation in the area that contributed to the creation of such a story, as people might have been more willing to believe such dark tales in a tough urban environment.
The main elements are centered around the barber Sweeney Todd. Firstly, his profession as a barber which he used as a cover for his murders. He would slit the throats of his customers. Then there's the aspect of Mrs. Lovett, who was involved in disposing of the bodies by making them into meat pies. The seedy and dangerous environment of 19th - century London also plays a role. It was a place where crime could thrive, and such a gruesome story could have some basis in the real - life hardships, vices, and criminal activities that were present in the city at that time.