A psychologist working with police investigating the murder of prostitutes in Ipswich says the recent deaths may be part of a larger killing spree.
The bodies of the three women were found near Ipswich
Five bodies have been found near Ipswich over the past fortnight.
Dr Ian Stephen said: "The killer is losing control and there is a compulsion taking over."
Police in Norfolk have confirmed they are looking at possible links with at least four unsolved cases of missing or murdered prostitutes in the county.
A Norfolk Police spokesman said: "We are continuing to check our databases to see if there is any information within the inquiries into prostitute murders that have occurred in Norfolk over recent years which may assist Suffolk Police with their inquiry.
"At this time there is nothing to suggest there are any links. However, we will continue to check and share information with Suffolk Police."
No-one has been charged with Michelle Bettles' murder
The bodies of Gemma Adams, 25, Tania Nicol, 19, and Anneli Alderton, 24, were found in rural locations around Ipswich between 2 and 10 December.
On Tuesday two more bodies were found which police believe "may well be" missing prostitutes Paula Clennell, 24, and 29-year-old Annette Nicholls.
A number of other women have vanished or been killed in similar circumstances in East Anglia over the past 13 years.
'Running out of victims'
Among the unsolved cases being looked at for possible links is the murder of Natalie Pearman, 16, who was strangled in Norwich in 1992.
Mandy Duncan, 26, of Woodbridge, Suffolk, vanished in 1993 while working as a prostitute in Ipswich.
Police fear Paula Clennell and Annette Nicholls have also died
Kellie Pratt, 29, disappeared from the red light area of Norwich in 2000 and Michelle Bettles, 22, was found strangled three days after disappearing from the same area of the city in 2002.
Her body was found in woods near Scarning and no-one has been charged over her death.
A Suffolk Police spokesman said officers were liaising with other forces, but added: "We are not looking at any other connections at the present time."
Forensic psychologist Dr Ian Stephen, who has worked on previous serial killer cases, says he thinks the murderer is likely to try to kill more women.
He said: "What may be an issue is that when he starts running out of prostitutes not becoming available, he will see any woman who's out on the street at night on their own as a prostitute and will target them as a possible victim."