No person who commits or conspires to commit the murder or voluntary manslaughter of a member, retiree, or beneficiary under a public retirement system shall receive any refund of contributions or any benefit under the public retirement system upon the death of the member, retiree, or beneficiary, even though the person so killing or conspiring is a named beneficiary for such refund of contributions or benefit. A plea of guilty or a judicial finding of guilt which is not reversed or otherwise set aside as to any such crime shall be prima-facie evidence of guilt for the purpose of applying the provisions of this Code section. All rights, interests, and entitlements to any such refund of contributions or benefit shall go to the secondary beneficiary designated by the member, retiree, or beneficiary, if a secondary beneficiary is designated and is living, upon the death of the member, retiree, or beneficiary, but otherwise to the member's, retiree's, or beneficiary's estate.