The Medical Examiner's Assistant was an uncredited courtesy role created by the film's producers for Jono Borden, an author and regional authority on the Borden family based in Halifax, Nova Scotia. He was asked to consult on his family's history and offered an appearance onscreen. The irony of his casting saw him assist in the fictionalized depiction of the postmortem examinations of his very real cousins, Andrew and Abby Borden, and in an alternate courtroom scene cut from the final film, present the exhumed skulls of his relations to the jurors.
Axe murders were not uncommon in the later 1800s and early 1900s throughout America, including cases where whole families were slaughtered in their sleep. Some famous cases include the Vacelet Family murders of 1878, Austin Axe Murders of 1884-5, Meeks Family Murders of 1894, and Villisca Axe Murders of 1912. A few known serial killers preferred the axe, such as Clementine Barnabet (active 1911-12) and Paul Mueller (1898-1912). Although an axe makes sense as a murder weapon at a time when reliable firearms were less available, many of these murders remain mysterious to historians and police authorities for the lack of discernible motive for whole families being slaughtered and the ability of the murderers to slip away leaving little or no evidence, which leads many researchers to consider period axe murders as a unique criminal phenomenon.
Christina Ricci has stated that she believes Lizzie Borden was innocent of the crimes she was accused of. She thinks the theory that an unknown drifter committed the murders is much more likely.
A few facts about the murder case help explain scenes in the film. The day before the murder when, in the barn, Emma tells Lizzie she will be going away for a few days, Lizzie appears to be cleaning bloody straw out of a coop. This is because her father had recently killed pigeons Lizzie had been trying to keep. Secondly, it may have appeared odd that Mrs. Borden went upstairs before her death to change bedding on a bed that looked impeccable already. In reality, the Bordens had a guest at the time, and Mrs. Borden was killed in the guest bedroom as she made the guest bed.
Based on the same real life events as The Legend of Lizzie Borden (1975), Lizzie (2018), Lizzie Borden: A Woman Accused (1995), The Lizzie Borden Chronicles (2015), Lizzie Borden Hash & Rehash (1995), The Strange Case of Lizzie Borden (2005), Lizzie Borden (2012) and The Older Sister (1956), and that are depicted in a lesser degree in Whodunit? The Greatest Unsolved Mysteries (1979), Wax Magic (1988) and Thin Lizzie (2015).