In 1914, in Wisconsin, seven people were murdered at Frank Lloyd Wright's home. To this day, no one knows the real reason for the massacre. 

Sources:
https://www.taliesinpreservation.org/history/
https://en.wikipedia.org/wiki/Taliesin_(studio)
https://www.history.com/news/the-massacre-at-frank-lloyd-wrights-love-cottage
https://en.wikipedia.org/wiki/Frank_Lloyd_Wright

https://centerforinquiry.org/blog/dispelling_a_ghost_at_fallingwater/

https://www.hauntedillinois.com/realhauntedplaces/dana-house.php

https://www.architectmagazine.com/design/frank-lloyd-wright-homes-with-haunted-histories_o