A 37-year-old man has been arrested on suspicion of murdering five women whose bodies were found at sites around the Ipswich area.
Supermarket worker Tom Stephens was arrested by police at his home at Trimley St Martin, near Felixstowe.
He is being held on suspicion of murdering prostitutes Gemma Adams, Anneli Alderton, Tania Nicol, Paula Clennell and Annette Nicholls.
Mr Stephens is in custody at an unnamed police station in Suffolk.
Police have said the inquiry is ongoing and have not withdrawn advice to women on the streets of Ipswich.
Meanwhile forensic scientists have been carrying out searches at the home of Mr Stephens' mother in the market town of Eye, Suffolk.
Neighbours said police officers arrived at the quiet cul-de-sac at about noon and began searching the semi-detached property.
Speaking in an interview with BBC News last week for background purposes, Mr Stephens said he "was probably the closest thing Tania [Nicol] had as a boyfriend".
"It wasn't a relationship like that, although Annette [Nicholls] in fact thought that we were an item," he added.
Mr Stephens, who worked for Tesco in Martlesham, said he had spoken to Miss Nicol's mother in the days following her disappearance.
He said he had known Miss Nicol for about six months but had known Miss Adams for 18 months, "about as long as I've known any of the girls".
Police had interviewed him at his home in Jubilee Close earlier in the investigation and had taken his mobile phone and laptop computer, he added.
Det Ch Supt Stewart Gull said: "We will not be naming the police station where the man is being held.
"As legal proceedings are now active, Suffolk Police will not be issuing further comments or appeals at this stage."
Detectives can hold Mr Stephens for 24 hours from the time he is booked into the custody suite.
Tom Stephens - important dates
November 2 - interviewed voluntarily by police
November 22 - house searched by police
December 12 - interviewed by the BBC
December 18 - arrested by police
He can be held for a further 12 hours with permission from a superintendent and up to 96 hours with permission from the courts.
Former Scotland Yard Commander, Roy Ramm, stressed police will not be jumping to conclusions.
"In any investigation like this, when you've got a number of young women who are all doing the same kind of thing, they're all acting as prostitutes in a very small area," he told BBC News.
"It's not inconceivable that a number of people will know all these young women, and could know them innocently. So I think the police will be proceeding very cautiously here."
The five dead women, aged between 19 and 29, were all found naked in rural settings within 10 miles of Ipswich.
They worked as prostitutes and all were drug-users. Their bodies were found close to the A14.
Forensic officers entered Tom Stephens' home in Suffolk
The body of Miss Adams, 25, who went missing on 15 November, was found in a brook at Hintlesham, Suffolk, by a member of the public on 2 December.
Tania Nicol's body was found by police divers searching areas of water at Copdock Mill, near Ipswich, on 8 December.
Miss Nicol, 19, was last seen after leaving her home in Ipswich on 30 October.
The body of Anneli Alderton, 24, from Essex, was found in woodland in Nacton, near Ipswich, on 10 December.
On 12 December detectives found the bodies of Paula Clennell, 24, and Annette Nicholls, 29, near the village of Levington.
Mr Stephens was arrested at 0720 GMT on Monday in the village, which is close to the A14 road between Ipswich and Felixstowe.
Trimley was last in the national news when 17-year-old Vicky Hall vanished on her way home from a nightclub in Felixstowe in 1999 and was found dead in a water-filled ditch at Creeting St Peter - 25 miles from Felixstowe.
It was believed she had been asphyxiated but a post-mortem examination proved inconclusive.
Police have not linked this case with the deaths of the five prostitutes.
On Monday they were unable to confirm Mr Stephens would be questioned about Miss Hall's murder.
The Association of Chief Police Officers say the number of officers deployed from forces outside Suffolk, under the control of the Police National Information and Co-ordination Centre, was the biggest ever for a murder inquiry.
In total 36 forces have sent 412 detectives, uniformed officers and police staff.