An 81-year-old Lincoln man accused of shooting his wife, who was suffering from advanced Alzheimer’s disease, has died at a hospital, authorities said.

John Kotopka was being held at the Lancaster County Department of Corrections awaiting trial for first-degree murder in the death of his wife, 78-year-old Janet Kotopka.

He died Thursday, jail officials said in a news release.

“While the cause of death has yet to be determined, Mr. Kotopka was being treated for a chronic medical condition,” the news release said.

As is normal protocol when an inmate dies in custody, a grand jury will conduct an investigation, the Lincoln Journal Star reported.

Kotopka shot his wife at their home on June 20, according to court records. She required constant monitoring because of her health problems.

Investigators said Kotopka told them he was “exhausted and couldn’t take care of her any longer” and was concerned about the financial burden if she went to a health care facility.