An inquiry into the shooting of a Cambridge doorman 19 years ago has been "filed" because police are "unable to push the investigation forward".
The body of Ian Grant was found on waste ground near Fulbourn Hospital in Cherry Hinton in 1995. He had been shot in the head.
Police reopened the case in November after describing new forensic evidence as a "significant breakthrough".
A spokesman said the case would be filed pending further evidence.
Detectives had said the "net was closing in" on those responsible for Mr Grant's death, and made an arrest in Cambridge in early December, a week after their fresh appeal.
The 49-year-old man was bailed and released without charge in April.
"We made significant progress in the investigation into the murder of Ian Grant and now have a much better understanding of the circumstances surrounding his death," a spokesman added.
"Unfortunately, however, we are not able to push the investigation further forward at this stage,
"We review all of our cold cases regularly and when any fresh evidence comes to light.
"This inquiry will not be closed but filed pending further evidence."
'Glimmer of hope'
Mr Grant had left his flat in nearby Speedwell Close on the evening of 14 November, with his body found shortly after midnight.
Police said Mr Grant had developed "a lot of enemies" through his own violence and trouble with other door companies.
His girlfriend's car had been set alight outside their flat two weeks before his murder.
In a statement released by police in November, Mr Grant's mother, Virginia Grant, said the new investigation "offers us a glimmer of hope that justice can finally be done".
Two men stood trial for Mr Grant's murder and were acquitted after trial at Norwich Crown Court in the 1990s.
The man released without charge had not previously been arrested in connection with the case.