As per Wikipedia:
In Riggs, a probate suit, the plaintiffs, Mrs. Riggs and Mrs. Preston, sought to invalidate the will of their father Francis B. Palmer; testated on August 13, 1880. The defendant in the case was Elmer E. Palmer, grandson to the testator. The will gave small legacies to two of the daughters, Mrs. Preston and Mrs. Riggs, and the bulk of the estate to Elmer Palmer to be cared for by his mother, Susan Palmer, the widow of a dead son of the testator, until he became of legal age.
Knowing that he was to be the recipient of his grandfather's large estate, Elmer, fearing that his grandfather might change the will, murdered his grandfather by poisoning him. The plaintiffs argued that by allowing the will to be executed Elmer would be profiting from his crime. While a criminal law existed to punish Elmer for the murder, there was no statute under either probate or criminal law that invalidated his claim to the estate based on his role in the murder.
The court eventually decided that the principle that one should not be able to benefit from one's own wrongdoing prevailed and Elmer did not inherit his grandfather's will.
Does Halacha recognize such a principle? Would a will be mevatel in a case like this?