Illinois ? A 90-year-old woman apparently has been living in a house with the bodies of her three siblings, one of whom may have been dead since the early 1980s, police in suburban Chicago said.

The bodies were found Friday morning by police who were called by a senior advocate, said Evanston police Cmdr. Tom Guenther.

The 90-year-old woman was taken to a hospital for observation. The Cook County medical examiner’s office said Saturday that the people had died of natural causes, but it would not say how long they had been dead.

The office has identified the dead as Anita Bernstorff, who was born in 1910, Frank Bernstorff, who was born in 1920, and Elaine Bernstorff, who was born in 1916. Anita Bernstorff was last seen alive in May 2008, Frank Bernstorff in 2003 and Elaine Bernstorff in the early 1980s, authorities said.

Neighbors described the woman as alert and aware, and they said she was well-liked on their close-knit block of large historic homes.