The 1920s saw a number of serial murderers in North America, but no one was more active than Earle Nelson, also known as "the Gorilla Killer or Dark Strangler." Nelson appeared to be able to kill at will as he wandered the country for more than a year, breaking into and out of suburban residences and boarding houses with ease.
Source Materials:
https://allthatsinteresting.com/earle-nelson
https://winnipegpolicemuseum.ca/wp-content/uploads/2021/03/the-stangler.pdf
https://www.therichest.com/shocking/15-facts-about-the-gorilla-man-earle-nelson/
https://the-line-up.com/gorilla-man-murders-earle-leonard-nelson
https://murderpedia.org/male.N/n/nelson-earle.htm
Schechter, Harold
(1998). Bestial: The Savage Trail of a True American Monster. New
York: Pocket Books