Anneli Alderton, who was three months pregnant when she was killed, was last seen on a train between Harwich and Colchester, wearing a black jacket, grey top and blue jeans. Her body was found in woods in Nacton, Ipswich on 10 December. She had been strangled to death.

Meanwhile, police have said they would be interested in speaking to a man who attended a memorial service for the five women who have been murdered. Assistant Chief Constable Jacqui Cheer said Suffolk police were looking to speak to Andrew Purdy, 44, a property developer from Holbrook.

Purdy spoke to press at a memorial service on Friday night in the Ipswich suburb of Copdock, which he attended with a teenage prostitute.

He told a reporter at the service that he knew all five women well.

"I just know them as friends really, " he said. "All I do is pull up in my car and chat. I think most of the girls are scared to go to the police.

Somebody has told them that their clients will get arrested and now whoever is responsible has gone underground."

Purdy also said he had met one of the victims, Paula Clennel, 24, a few weeks before she was murdered.

"She asked me to help her come off drugs, " he said. "She said to me: 'I know I have done wrong in the past, I know I have nicked money off you and I know I have got in with the wrong people. I want my life back.'" The 19-year-old prostitute who accompanied Purdy to the service, and wished to remain unnamed, told reporters she had seen victim Annette Nicholls (29) the night she disappeared. "I spoke to her and she was fine, " she said, adding: "All the girls are scared and hoping that police find the killer."

Assistant Chief Constable Cheer urged Purdy to get in contact: "He is someone we would be interested in speaking to. He may have information that could help."