Two more people have been arrested after a woman's body was found at a disused railway line in Warwickshire.
Twenty-seven-year-old Gemma Hayter's body was found by a jogger off Hillmorton Road in Rugby at about 0530 BST on Monday.
Her cause of death is unknown but police said she had been assaulted.
A 19-year-old man and a woman, 21, both from Rugby, have been arrested on suspicion of murder. A 35-year-old man arrested on Monday has been bailed.
The man was also arrested on suspicion of murder.
A post-mortem examination carried out on Monday failed to establish the cause of death.
Police would like anyone who knew Ms Hayter, who lived in Biart Place, Rugby, to contact them.
They would also like to hear from anyone who was on the stretch of railway line, between Hillmorton Road and Pytchley Road, where the railway station used to be, between 1800 BST on Sunday and 0600 BST on Monday.
Det Ch Insp James Essex, who is leading the murder investigation, said: "The stretch of disused railway line is very popular with dog walkers and joggers and it is possible that someone may have seen some suspicious activity in the 12 hours before Gemma's body was discovered."