An attempt to check for fibres sticking to Elaine Doyle's naked body may also have preserved DNA from "a third party", the murder trial was told.
The High Court in Edinburgh heard about the obstacles confronting police when Elaine's body was found in Greenock in June 1986.
A veteran forensic scientist said: "It was a particularly difficult crime scene to manage."
The exposed body in an area overlooked by houses meant the examination of the crime scene had to be completed as quickly as possible so that Elaine's body could be taken away.
Keith Eynon, former head of forensic support with Strathclyde Police, recalled how he was called to a lane off Ardgowan Street where the 16-year-old girl was lying.
He told the trial: "The body was exposed. There were people milling around in the area.
"I was told the deceased's parents lived nearby so there were a lot of issues over and above the normal scene examination."
The problems led to "a certain urgency", said Mr Eynon who retired 20 years later.
Mr Enyon, 68, told the trial: "DNA didn't exist as far as forensic scientists were concerned." He went on to tell how he checked for possible footprints, but the ground was too hard.
He could see no obvious bloodstains. The next step was to check for fibres which might be clinging to the body and might link the dead girl to her killer. He described how broad adhesive tape was used to try to pick up hairs or fibres, something which had to be done before the body was moved.
John Docherty, 49, of Hunters' Quay, Holiday Village, Dunoon, denies murdering jeweller's assistant Elaine. He claims at the time he is alleged to have stripped and strangled the 16-year-old he was at home with his parents who are no longer alive.
The trial continues.