In trusts and estates law, the slayer rule says that a murderer cannot retain a property interest in his/her victim’s estate. It is a common law of inheritance where a murderer is prohibited from inheriting the property of whom s/he has murdered. The slayer rule allows courts to presume the murderer disclaims his/her property interest, and therefore behave as though the murderer predeceased the victim. This has the effect of disqualifying the murderer from receiving property from the estate of the victim. The rule applies only if killing was felonious and intentional. As the doctrine is applicable to civil law, it is only needed to prove with evidence the wrongful killing.
An example of a state slayer statute(California) is as follows:
Cal Prob Code § 250 reads:
(a) A person who feloniously and intentionally kills the decedent is not entitled to any of the following:
(1) Any property, interest, or benefit under a will of the decedent, or a trust created by or for the benefit of the decedent or in which the decedent has an interest, including any general or special power of appointment conferred by the will or trust on the killer and any nomination of the killer as executor, trustee, guardian, or conservator or custodian made by the will or trust.
(2) Any property of the decedent by intestate succession.
(3) Any of the decedent's quasi-community property the killer would otherwise acquire under Section 101 or 102 upon the death of the decedent.
(4) Any property of the decedent under Part 5 (commencing with Section 5700) of Division 5.
(5) Any property of the decedent under Part 3 (commencing with Section 6500) of Division 6.