An 89-year-old man stabbed his wife to death in their Cherry Hill home yesterday, then stabbed himself, authorities believe.

Maria Gniotek, 77, was found dead about 11:30 a.m. in the home she shared with her husband, Aleksander Dziarski, according to the Camden County Prosecutor's Office. She was killed with a kitchen knife.

Dziarski suffered what appeared to be self-inflicted stab wounds and was being treated yesterday at Cooper University Hospital in Camden.

Authorities have not charged Dziarski, but Jason Laughlin, a spokesman for the Camden County Prosecutor's Office, said investigators did not think anyone else was involved.

"They were the only ones there," he said. "We're just not entirely sure of how this happened."

Authorities are investigating the circumstances surrounding the slaying. Dziarski is in poor health, Laughlin said, but the spokesman would not comment on what might have led Dziarski to attack his wife.

Gniotek and Dziarski lived at the end of the 700 block of Longwood Avenue, just off Route 38, in a modest, one-story white house with a well-kept yard.

Neighbors said they didn't know the couple well. Tom Lampropoulos, who lives down the street, said that the couple moved in at least five years ago, but that he didn't talk to them other than to say hello.

"They seem like nice people," he said.

Contact staff writer Allison Steele at 856-779-3838 or asteele@phillynews.com.