BH was always fairly close with his father. John Scott Harrison - uniquely the son of a president and the father of a president - was himself an Ohio Congressman. He wrote little Ben a lot of letters full of good political advice.
By the time he died, Ben was already a well-known trial attorney and frequently in the running for Indiana's Governorship or Senate seat (although at the time of his father's death I don't think he had yet claimed his eventual Senate win).
When John Scott died, all the surviving Harrison boys gathered in North Bend, Ohio for the funeral. At the burial, they noticed that a neighboring grave, that of their recently deceased relative August Devin, was disturbed. Suspecting a grave robbery, Ben's brother John Jr. vowed to investigate on behalf of the Devin family.
Body snatching was a common practice at the time, as corpses were needed for medical education, but demand outweighed supply. In fact, many families would hire someone to guard the grave of their deceased loved one for the first month after their death, which was prime body snatching time.
John Jr. visited the Ohio Medical College, where it was known that stolen corpses arrived at night through a chute. They got a janitor to show them around, and eventually found a rope hanging in an elevator shaft, with what looked like a body suspended at the end of it. When they pulled up the rope, John Jr. discovered the body - not of Augustus Devins - but of his own father.
DUH DUH DUMMMM.
I cannot imagine the horror of that moment. Clearly the Harrisons were furious, and the Ohio Medical College should have been mortified that they had just pissed off one of the best trial lawyers in the west. Bizarrely, they were not. Their spokesman emerged as a cavalier jerk who was brashly unapologetic. His basic response was, you guys don't get it, we really need bodies, this is how we teach doctors. The college claimed ignorance of who the body snatchers were and who at the college was responsible for receiving them (although a night janitor was the obvious suspect.)
Despite how insane these claims were, the College did in fact avoid all culpability in the inevitable Harrison-led trial, letting a few staff members take the fall. Harrison himself seemed to want to move on from this fiasco as quickly as possible. After re-burying his father, he was rarely heard to mention him for the rest of his life.