CHICAGO — A 34-year-old pregnant woman is dead following a house fire early on Chicago’s West Side.

Police said officers responded to a residential fire just after 2:40 a.m. Monday in the 5000 block of West Gladys Avenue in the South Austin neighborhood.

Upon entering, police said Chicago firefighters discovered a 34-year-old woman unresponsive, and she was pronounced dead at the scene.

Relatives have identified the woman as 34-year-old Stephanie Haynes. They say she was a mother of four and was five-months pregnant.

Haynes’ sister, Lesley, said police told her Stephanie was dead before the fire started. Lesley also revealed her sister suffered from mental illness, and had just moved to Chicago from Seattle a year ago.

The home belonged to Haynes’ late grandmother, and Haynes was the only one home at the time of the fire.

A cause of death for Haynes remains unknown pending an autopsy.

The incident remains under investigation by police and arson detectives.