At Hawley Harvey Crippen's trial, the scar was identified as being from an operation Cora Crippen had undergone. The remains were therefore those of Cora Crippen.
...Or were they!?
Dun. dun. DUNNNN!
In 2007, forensic science researchers at the prestigious (and, coincidentally, server hosts for your favorite website) Michigan State University concluded based on a mitochondrial DNA evidence that the body found in Dr. Crippen's cellar was not that of Cora Crippen.
It is perhaps ironic, then, that Crippen was essentially convicted based on the forensic evidence presented in court. The facts of the case were plain: there was a body under Dr. Crippen's cellar, it had been poisoned, and it was in such a state of viscera that only a small abdominal scar was used to positively identify the remains as those of the doctor's late wife.
So when a poison expert from Grand Rapids decided to "re-open" the case based on some of the inconsistent evidence, he got permission from the Royal London Hospital Archives and Museum to examine DNA from the small piece of skin containing the tell-tale scar to identify it as Cora Crippen's, one and for all.
The detective business took two steps. First, some nifty labwork to break through the pine sap and formaldehyde used to preserve the tissue, and second, finding living female relatives of Mrs. Crippen to provide a comparison of the DNA.
And the verdict? Not Cora Crippen.
So while it's true that somebody was down underneath that poor doctor's cellar, it wasn't his wife, and since Dr. Crippen went to the gallows protesting his innocence, it seems like this case will join that other famous turn of the century one in the "whodunit?" pile ...