Albert Einsteins brain was stolen: The man who performed the autopsy on Einstein's body shortly after he died was a Princeton pathologist by the name of Thomas Harvey. Harvey removed the brain for examination, as is customary during autopsies, but he never replaced it. At the cost of his job and reputation, Harvey instead placed it in a jar of formaldehyde and took it home!
Over the next 40 years, he sent bits of the brain to leading neuroscientists for them to study. He felt that stealing the brain was his scientific duty! What is left of the brain now resides back at Princeton where it started - Harvey tried to return it to Einstein's daughter at one point, but she didn't want it, so he gave it back to the university.