A 38-year-old man from the Wisbech area has been arrested on suspicion of murder after a woman's body was found in a burned out caravan.
A 47-year-old woman has also been arrested on suspicion of conspiring to pervert the cause of justice.
The body was discovered by police following a fire at a travellers' site at Turf Fen Bridge at Murrow, Cambridgeshire, early on Saturday.
A post-mortem examination on the woman's body is to be carried out.
Cambridgeshire police are urging anyone with information to come forward.