A 13-year-old girl arrested on suspicion of murder after a man's body was found in a country lane has been released without charge, police said.
A 47-year-old woman and three men, aged 31, 27 and 21, all from South Yorkshire, remain in police custody this morning.
A murder investigation was launched by Nottinghamshire Police after the man was found in a lane near the village of Everton, close to Bawtry, on Saturday.
Officers from South Yorkshire Police have been assisting with the investigation.
A cordon and police guard remain in place where the body was found while a forensics team carries out investigations at the scene.
The results of a post-mortem examination were inconclusive.
Inquiries are under way to identify the victim and trace next of kin.
Nottinghamshire Police want to speak to anyone who saw anything unusual in the area between Friday and the afternoon of Saturday February 2.
Anyone with information should contact the force on 101.