One of two women found dead in woodland near Ipswich in Suffolk was strangled, a post-mortem examination has revealed.
Remains found at Levington on Tuesday are thought to be those of prostitutes Paula Clennell and Annette Nicholls but have not yet been formally identified.
Five women have been found dead in the area since 2 December. One body remains in the woodland where it was found.
Officers are trying to establish if a jacket dragged from the River Orwell and a handbag are significant.
They have also said they would like to speak to the driver of a blue BMW car that Anneli Alderton, a murdered prostitute from Essex, was reported as getting into before her body was discovered.
Ms Alderton, whose body was found on Sunday, had also been strangled.
Police have now confirmed that four of the five bodies were those of women who had been murdered.
Three of those have been identified as Gemma Adams, Tania Nicol and Anneli Alderton.
The dead woman whose cause of death was revealed on Thursday has not been formally identified.
Det Ch Supt Stewart Gull said: "Formal identification of the body is taking place. The body of the other woman found near Levington remains at the site and is likely to be recovered later on Thursday.
"It too will be the subject of a Home Office post-mortem examination."
Police have previously said they believed these two bodies to be those of Ms Clennell and Ms Nicholls.
Mr Gull said the force had received a number of calls from the public about clothing found at different locations across Ipswich.
But he said he still needed more information on certain key things, including the clothing worn by the murdered women.
Police said they hoped to recover the fifth body later on Thursday
"When she was last seen on 30 October, Tania Nicol was wearing a light coloured top, mid-blue cut-off jeans, and pink sparkly high heeled shoes. This is the sort of clothing that I'm particularly interested in locating.
"Gemma Adams, last seen on 15 November, was wearing a black waterproof waist-length jacket with a hood and a zip up the front, light blue jeans with studs on the pockets, a red top and white and chrome Nike trainers.
"She was also carrying a black bag.
"If anyone sees any of these items, please contact Suffolk Police immediately."
Mr Gull made some specific appeals in relation to Anneli Alderton, whose body was found at Nacton on Sunday 10 December.
"We want to know where she was and who she was with between Sunday 3 December, when we believe she caught a train from Harwich to Colchester, and where she was subsequently seen on Thursday 7 December and mistaken for a mannequin.
"Also there are two lay-bys on the old Felixstowe road, just a few hundred yards from the site where the two women were found.
"We know these are well used by passing motorists and I want to hear from anyone who saw any suspicious activities in these lay-bys since Sunday."
Police also want to hear from a prostitute who told a member of the press that Ms Alderton was seen getting into a blue BMW car.
"We want to know more about this and when it happened," he said.
Police said they had received 5,500 calls to their hotline and more than 1000 e-mails from members of the public.
They also said they had been joined by 244 officers from nine other police forces and said that number is continuing to rise.