Detectives are continuing to question a 28-year-old man arrested on suspicion of murder in Newmarket.
The man was detained after a woman was stabbed at a property in Brickfields Avenue.
Due to the fact that there had been previous contact between the victim and Suffolk Constabulary prior to the incident, the matter has been referred to the Independent Office for Police Conduct for their assessment, in line with agreed protocols.
Police were called to Brickfields Avenue just after 9.30pm yesterday.
Police, paramedics and the air ambulance were in attendance, but the woman died at the scene.
A cordon has been in place at the property throughout today and a road closure of Brickfields Avenue also remains in place.
The 28-year-old suspect is currently at Bury St Edmunds Police Investigation Centre, where he was taken for questioning.
The suspect and the deceased were known to each other.
Anyone with information is asked to contact the Major Investigation Team either by using the online portal: https://mipp.police.uk/operation/363719N31-PO1 or by calling 101 and quoting reference 37/3358/20