Detectives investigating the deaths of five women in Suffolk have been given an extra 36 hours by magistrates to question a suspect.
The women were found naked between 2 and 12 December
The suspect, named locally as Stephen Wright, 48, was arrested at his Ipswich home on Tuesday morning.
Suffolk Police officers had until Wednesday afternoon to either apply to the courts to continue questioning of Mr Wright, or charge or release him.
Another suspect Tom Stephens, arrested on Monday, is also being quizzed.
Police have been given permission by magistrates to continue to question Mr Stephens, of Trimley St Martin, near Felixstowe, until Thursday, when officers may seek the go-ahead to question him for a further 24 hours.
On Wednesday morning the inquests into the deaths of four of the women opened and adjourned.
The hearing at Ipswich Coroner's Court found no clear cause of death for Tania Nicol and Annette Nicholls.
Anneli Alderton was asphyxiated and Paula Clennell died from compression of the neck, coroner Dr Peter Dean said.
The inquest into the death of another victim, Gemma Adams, was opened last week.
Dr Dean offered his condolences to the families of the murdered women, who were not at the hearing.
Det Supt Andy Henwood told the inquest Miss Nicol had left her home in Ipswich on 30 October to go to work as a prostitute in the town centre.
She failed to return home and was reported missing, he said. Her naked body was found on 8 December in Belstead Brook at Copdock, near Ipswich.
The naked body of Miss Alderton was discovered beside a road in the village of Nacton, near Ipswich, by a member of the public on Sunday 10 December.
Miss Clennell was reported missing in the early hours of 10 December after she went to work in Ipswich's red light district.
Mr Henwood said that on 12 December the naked body of a woman was discovered on the Old Felixstowe Road and was later identified as Miss Clennell.
Annette Nicholls was reported missing on 11 December and was last seen by her mother on 4 December.
When officers attended the site of Miss Clennell's body at Levington, the Suffolk Police helicopter discovered the body of a second naked woman nearby.
The inquest heard the body was later identified as Miss Nicholls. A post-mortem examination had been unable to establish the cause of her death.
Forensic teams have been searching an address in the London Road area of Ipswich where Mr Wright was arrested.
Former special constable Mr Stephens was arrested at his home at Trimley St Martin.
Police have not confirmed or denied the identities of the people in custody.
Despite making two arrests, police have stressed that the investigation is ongoing and members of the public should remain engaged by passing on any information that they believe may be useful.
Forensic scientists and police teams have been carrying out searches at Mr Stephens' home, in Jubilee Close, and his mother's home in the market town of Eye, Suffolk.
The five dead women were all found naked in rural settings, within 10 miles of Ipswich and close to the A14.