Authorities were investigating the deaths of a man and a girl in a fire Thursday night in the Douglas Park neighborhood on the Southwest Side.

Emergency crews found the 5-year-old girl and 51-year-old man dead about 9 p.m. in the 1600 block of South California, according to Chicago Police.

Police investigate a fatal fire about 12 a.m. Friday, July 6, 2018 in the 1600 block of South California Ave in Chicago. | Justin Jackson/ Sun-Times

Detectives were investigating the incident as a domestic-related murder-suicide, police said.

The Cook County Medical Examiner’s Office has not released the identity of either person and autopsies Friday did not rule on the cause and manner of their deaths pending further investigation.