Alan Stewart was the first officer to arrive at the lane in Greenock, Inverclyde, where the 17-year-old’s remains were found in June 1986.
The High Court in Edinburgh heard how Mr Stewart – who was a Police Constable – saw the teenager’s unclothed body on the ground with her clothes lying nearby.
He told the court he also thought he could see Elaine’s bra hanging off her body.
Mr Stewart, 55, told prosecution advocate John Scullion: “I saw the naked body of a female. She was lying on her side. Some clothes were nearby. I remember a blue leather jacket and a white floral dress and a pair of shoes.”
Mr Stewart, whose address was given as care of Police Scotland, was giving evidence on the second day of proceedings against John Docherty, 49, of Dunoon, Argyll, who denies murdering Elaine in Greenock on June 2, 1986.
Mr Stewart told Mr Scullion that he was on duty on the day in question. He was driving around the west end of Greenock when he was instructed to go to a lane off Ardgowan Street.
The court heard that 2 June was a public holiday.
A member of the public, who had earlier telephoned police, told Mr Stewart where Elaine’s body was located.
Mr Stewart, who retired from the police last year, told the court Elaine’s clothes were beside her.
Defence advocate Donald Findlay asked Mr Stewart whether there was any doubt as to whether Elaine was dead. Mr Stewart replied: “No”. The court heard Mr Stewart then secured the area and made a log of the police officials who visited the scene.
The court also heard evidence from another retired police officer, William Kennedy. Mr Kennedy, 56, was at the location where Elaine’s body was discovered. The jury heard he was told by a senior CID officer to cover Elaine’s body with a blanket, which was taken from a police car.
The court was told the blanket could have “contaminated” or “decontaminated” evidence from Elaine’s remains.
When Mr Findlay asked Mr Kennedy what he knew about crime scene contamination in 1986, Mr Kennedy replied: “Next to nothing, to be honest.”
Mr Docherty has pleaded not guilty to a murder charge which alleges on June 2, 1986 in a lane near Elaine’s home in Ardgowan Street, Greenock, he seized her by the hair, struck her on the head and either removed or compelled her to remove her clothing.
The trial before Lord Stewart continues.