The detective heading the hunt for the serial killer thought to be targeting prostitutes in Ipswich today said officers were "eager" to speak to the driver of a blue BMW.

One of the dead women, Anneli Alderton, is reported to have climbed into a blue BMW in Ipswich last week. The information was passed to police after another Ipswich prostitute reported the sighting to journalists. Detective Chief Supt Stewart Gull was today asked whether officers were "eager to speak" to the driver of that car.

He replied: "We are still trying to piece together Anneli’s last movements."

Mr Gull added: "We have received a significant volume of calls from across Suffolk and further afield and a lot of interesting information has come in. That is just one aspect we are looking at."

Mr Gull said detectives were not specifically linking the deaths of the five women to any previous killings or disappearances of prostitutes in East Anglia or in other parts of the UK.

"We are clearly aware of a number of other crimes," he said. "We will look at any similarities but at the moment our focus is here in Suffolk and on the crimes we are currently dealing with.

"We are not at this stage linking these murders to anything else."

Mr Gull also said detectives were not "at this stage" attaching any significance to any items of women’s clothing handed in to police in recent days.

"We need to find the clothes the murdered women were wearing and we have appealed for help with that," he said. "We have received a number of items of clothing, but we have not yet established exactly what the girls were last wearing. Whatever clothing we have received has been seized and will be assessed in due course."

The bodies of five women have been found in isolated locations near Ipswich during the past two weeks. Detectives say three of the women were Ipswich prostitutes who had been murdered.

The pathologist was due to complete post-mortem tests on the bodies of the fourth and fifth women today.

Police launched a murder investigation on December 2 when the body of Gemma Adams, 25, was found in a stream at Hintlesham. On December 8 the body of Tania Nicol, 19, was found in the same stream at Copdock.

On Sunday the body of Anneli Alderton, 24, was found in woods at Nacton. The bodies of the fourth and fifth women were found in woods at Levington on Tuesday.

Police believe that they are the bodies of missing Ipswich prostitutes Paula Clennell, 24, and Annette Nicholls, 29.