The probate court agreed that the presumption must be invoked, and conducted an evidentiary hearing to determine the likely fate of the will. See In re Estate of Fuller, 119 N.H. 132, 135 (1979). Much of the testimony at the hearing concerned Douglas' relationship with his family.

A will, for example, must be made and executed with startling formality, but if lost or misplaced may be proved by oral evidence. E.g., In re Estate of Fuller, 399 A.2d 960, 961 (N.H. 1979). Indeed, the whole tendency of the law of evidence governing documents is to demand the original if available but to forgive its absence if explained.

Because the petitioner met her burden of producing evidence to demonstrate a potential failure of due execution, the trial court correctly found that the presumption of competency was rebutted and the respondent had to prove capacity by a preponderance of the evidence. See In re Estate of Fuller, 119 N.H. 132, 135, 399 A.2d 960, 961 (1979). Second, the respondent argues that no reasonable trier of fact could have found that the testatrix lacked the testamentary capacity to execute her will in April 1992. A thorough review of the record convinces us that the evidence supports the trial court's ruling that the testatrix lacked capacity to execute her April 1992 will. All the testifying physicians agreed that the medical evidence indicated the testatrix had Alzheimer's disease in April 1993, a year after the will's execution.