At the post mortem, it was established that Christine was killed first, then Helen. But this was one of the few certainties detectives could establish. “When you look back to 1977 it’s almost looking back to a dark age. Forensic science was very much still the same as it had been in the early part of the century...We didn’t really have that much more in terms of technique or knowledge than the Victorian detectives had who investigated the original Jack the Ripper murders… forensically, it was all about hairs, fibres and blood and not much else really.  We didn’t have any knowledge of DNA at that time. What we had was very, very good, Crime Scene Technicians.”Tom wood, Former Det. Chief Constable, Lothian & Borders Police These technicians would scrupulously select, seal and label the evidence from the bodies, from their clothes and from the crime scene. And one of the best forensic scientists back at the lab was Lester Knibb.“We were involved in the examining of every item that had been recovered from the scene...every bit of clothing...the ligatures and vaginal swabs and other swabs from parts of the body were all submitted...Our initial job was to examine the clothing and recover any trace evidence that might be present on it, particularly fibres that might have been transferred during the initial assault...in other words the last things that they might have been touching while they were wearing these items.” “We had in these forensic samples a kind of, a code, a kind of a Rosetta Stone, if you like...we knew there was something very important but we just couldn’t read it. We didn’t have the knowledge, we didn’t have the science to decipher it, yet.”Tom Wood In a pre-computer age, where murders were still recorded on cards, it was this almost prescient preservation of evidence that would be the killer’s undoing. But until forensic science caught up with the evidence, the police were reduced to trying to trace everyone who had been in the World’s End pub. To help those whose memories might have been affected by alcohol, it was decided to risk using an identikit picture.“Identikit pictures are dangerous because if the victim’s recollection of someone they’ve seen is inaccurate you end up looking for someone who doesn’t exist.”Tom WoodThis lead to hundreds of thousands of man-hours as the police followed up thousands of leads. But after the biggest manhunt in Scottish police history, the police had nothing. As former Detective Chief Constable, Tom Wood put it;“...the enquiry didn’t close down. It closed itself down because we didn’t have any other leads.” Throughout the following decades new leads were followed up and statements rechecked but all with the same lack of results.