Justice Lawrence Wargrave, otherwise known by his mysterious alias “Mr. Owen,” is a recently retired judge. He is often described using reptilian imagery, such as when Dr. Armstrong first describes him as having a “frog-like face […] tortoise-like neck […] hunched up attitude […] and […] pale shrewd little eyes” (30). Christie doesn’t reveal that Justice Wargrave is the murderer until the very end of the novel in the form of a manuscript that Justice Wargrave put into a bottle and tossed out to sea. Justice Wargrave writes in the manuscript, which essentially is a confession letter, that from an early age he always took a sadistic pleasure in seeing or causing death; however, he also always felt a strong commitment to justice. To satisfy these contradictory urges, he joined the legal profession as a judge. Eventually, condemning the guilty to death was not enough and he longed to commit a murder himself.

Throughout the novel, Justice Wargrave is cold, cruel, and highly intelligent, all characteristics that should make him a prime suspect. However, due to his leadership amongst the group and his reputation as a professional man of law, he is rarely seen as a suspect amongst the guests.