Prosecutors have failed to prove "beyond a reasonable doubt" that an accused man murdered five women in Suffolk, a jury has been told.
The five women were found dead around Ipswich in December 2006
But Steve Wright's defence admitted it had been demonstrated he had "a close association" with the women.
The prosecution acknowledged police could not rule out "another or others" being involved but said Mr Wright was "the one common denominator".
Mr Wright, 49, on trial at Ipswich Crown Court, denies murder.
The naked bodies of Tania Nicol, 19, Paula Clennell, 24, Anneli Alderton, 24, Annette Nicholls, 29 and Gemma Adams, 25, who all worked as prostitutes, were found in and around Ipswich over a 10-day period in December 2006.
Timothy Langdale QC, representing Mr Wright, was making his closing speech to the jury at the end of the trial.
"In this remarkable and unusual case the prosecution have put before you a mass of evidence," said Mr Langdale.
"They suggest that it presents an overwhelming case against this defendant.
"But, we ask, an overwhelming case of what?
"All that evidence adduced by the prosecution demonstrates, you may think, quite clearly, is a close association between Steve Wright and the five young women who died - and a close association between them and him not many hours before they died.
"That is not in dispute.
"What all the evidence does not do, we suggest, is demonstrate beyond a reasonable doubt, to use an old fashioned expression, that Steve Wright is responsible for their deaths."
Steve Wright, 49, denies killing the five women
He told the jury that Mr Wright had had sex with other prostitutes at the time the five women disappeared, who had not been harmed.
"It is far from being the case on the evidence that every time Steve Wright went with a prostitute the girl ended up dead," Mr Langdale said.
Jurors have been told the defendant's DNA was found on three of the women's bodies and that forensic evidence from his clothes, home or car links him to all five.
The closing speech followed the prosecution's summing up to the jury.
'Sex not sufficient'
Prosecutor Peter Wright QC said the defendant needed "more than sex".
"The reality is Steve Wright simply could not restrain himself," he said.
"He embarked on a course of conduct that deprived these women of their lives.
"Sex with them was not sufficient. He needed more and he achieved it at their expense," he added.
Steve Wright was the one "common denominator" in the case, he said.
The jury was told detectives may never know whether more than one person was involved in the murders of the women.
The prosecutor said one particular individual - supermarket worker Tom Stephens - could not be eliminated, but that suspicions did not equate to evidence.
"Was more than one person involved?" Mr Wright said.
"We say the answer is simple. We may never know. No one saw the crimes being committed.
"The offences may be the work of one man but we cannot exclude the possibility that another or others may have had a hand in each of these deaths."
He said the defence team had "raised the spectre of Tom Stephens" who was arrested on suspicion of murder and released without charge.
"There is no evidence that provides him with an independent verifiable alibi that would conclusively rule him out," the counsel said.
"Mere suspicions in respect of Tom Stephens cannot be converted into evidence."
The trial adjourned.