A 91-year-old man is facing a first-degree murder charge after revealing to investigators that he fatally shot his 87-year-old wife, who had Alzheimer’s disease. Police revealed that the motive behind the murder was to keep a promise he made to her: never to put her in a nursing home, Law&Crime revealed

William Albert Lippold is charged with premeditated first-degree murder with a firearm in the death of his wife, Mary Lippold, according to court records.

St. Johns County sheriff’s deputies responded to the couple’s home on Como Court on Saturday after the couple’s son called 91. He reported that his father had killed his mother, as shown in the probable cause affidavit. Lippold and his 63-year-old son, David, came out of the house when deputies arrived, and then they were removed from the premises. Authorities revealed that Lippold confessed on the spot, telling deputies simply that he had shot his wife.

Deputies found Mary Lippold dead in the master bedroom, next to a firearm, a spent shell casing, and a note.

David Lippold told investigators his father had phoned him that morning, saying something was wrong and asking him to come over. When he arrived, his father asked him to sit down before revealing what had happened, the affidavit states. David Lippold said he then found his mother’s body and was told his father had tried unsuccessfully to suffocate himself with a plastic bag afterward.

David Lippold said his father had been his mother’s sole caregiver.

William also reportedly told detectives he had spent about a month planning the killing. He described his wife as blind and suffering from Alzheimer’s, and said he had long promised her she would never end up in a nursing home, which he said motivated the shooting. He also referenced messages exchanged with his adult children about the strain of caregiving,

Investigators said Lippold acknowledged buying the gun used in the shooting shortly beforehand and visiting a firing range to practice with it. A neighbor told deputies they heard what sounded like a gunshot around 11 p.m. the night before the killing was reported.

Neighbors described the Lippolds to Jacksonville TV station WJXT as a well-liked couple whose declining health had been visible to those nearby. William remained in custody on Wednesday on the murder charge. Court records did not show whether he had retained an attorney or when he is next due in court.

Disclaimer: Inquisitr could not independently confirm the facts of this incident and is reporting based on the information available.