Sheffield house fire: Murder probe after man's body found
A murder investigation has been launched after the body of a man was found following a house fire.
The body of Robert Kostucha, 42, from Poland, was discovered at a property in Sackville Road, Sheffield on Saturday morning, South Yorkshire Police said.
A post-mortem examination was inconclusive and further tests are due to take place, the force said.
Two men, aged 35 and 38, and two 19-year-old women were arrested on suspicion of murder.
They have since been released while inquiries continue.
Officers remain in the area and witnesses are being sought. A cordon is in place.