Police in Lancashire believe they may have solved a 35-year-old murder case thanks to advances in DNA evidence.
Joan Harrison, 26, who was found dead in a derelict garage in Preston in 1975, was once thought to have been killed by the Yorkshire Ripper.
But detectives said DNA found at the scene matched that of Christopher Smith from Leeds, who died in 2008 aged 60.
The Crown Prosecution Service said police had enough evidence to charge him with murder if he were still alive.
Miss Harrison, who had worked as a prostitute, was found dead in a garage in Berwick Road, in the Avenham area of Preston, on 20 November 1975.
A bite mark was found on her breast and several items of jewellery were missing, including two gold wedding rings belonging to the twice-married victim.
'Put record straight'
Smith had a DNA swab taken when he was arrested for drink driving in 2008, but he died six days later from a terminal illness.
Investigations have revealed he had criminal convictions ranging from assault and theft to sex attacks.
Police said a three-page note - written by Smith the day before he died - in which he seemingly admitted the murder was also found at his home.
The note read: "Two how (sic) ever it concerns I would like to put the record straight. I can't go on with the guilt.
"I have lived with it for over 20 years.
"I am truly sorry for all the pain I have caused to anyone. Please believe me when I say I am sorry.
"I love my grandkids and my daughter. I cannot go back to prison anymore. Please God help my family who I worship. I have been out of trouble for over 20 years so please Gold help me.
"I am so sorry. God forgive me. I love you all forever."
It is understood he did not know his victim and may have come across her by chance after being released from a prison sentence he had served in the area.
Det Ch Supt Graham Gardner, head of crime for Lancashire Constabulary, said: "Advances in DNA interpretation over the years has finally allowed us to identify Smith as the man at the scene of Joan's murder.
"That fact, coupled with other evidence we have gathered over recent months, has been sufficient to convince the Crown Prosecution Service that Smith would have been charged with her murder, had he been alive today."
Mrs Harrison's family are being offered support by trained officers.
At one point in the murder investigation, police were distracted by hoaxer John Humble, from Sunderland, who had tried to convince officers that Peter Sutcliffe, the Yorkshire Ripper, had killed Miss Harrison.
It was Humble's letters in 1978 to West Yorkshire Police that first mentioned Miss Harrison's murder, which had not been formally linked to the seven Ripper murders.
Because saliva from the letters was linked to the same blood group as her killer's, police connected this death with the Ripper murders.
Humble's hoax, including his so-called "I'm Jack tape", clouded the investigation.
Internal police documents revealed that because Humble had a North East accent, this led officers investigating Miss Harrison's murder to focus on men who came from that region.
By the time Sutcliffe was caught and convicted in 1981, a total of 13 women had been murdered.
Humble was caught in a cold case operation in 2006 and jailed for eight years after admitting perverting the course of justice.