The identity of an elusive American serial killer and rapist could finally be revealed by a groundbreaking Nottingham research project matching voices to faces.
Experts at Nottingham Trent University are working with evidence connected to the East Area Rapist, who murdered 12 people and committed 45 sex attacks in California from 1979 to 1986.
He has never been caught and Californian police and the FBI launched a new ‘cold case’ investigation appeal in June.
His exact appearance is largely a mystery as he normally wore a balaclava, and a handful of police sketches from witnesses accounts are inconsistent.
But evidence collected over the years also includes audio tapes of chilling follow-up calls he made to victims to terrorise them.
The recordings are now being used by psychologists at the university’s School of Social Sciences, who completed a study earlier this year suggesting people can work out someone’s appearance just by hearing their voice.
They are now using this discovery to see if they can narrow down the likenesses of the killer to one police drawing, or narrow down lists of suspects.
Although the study is not part of the official investigation, researchers plan to share the results with the Sacramento County Sheriff’s Department, which is leading the enquiry.
“We know that drawing links between faces and voices could produce some fascinating results,” said Dr Harriet Smith, a psychologist leading the research in Nottingham.
“Based on our earlier work, it seems that people make similar judgements about strangers’ faces and voices, even when the two are not encountered together.
“This knowledge could be helpful in narrowing down a list of suspects, or establishing which one of several composites best depicts the perpetrator.
“Analysing the way in which participants respond to the voice recordings and facial composites could help us to develop new ways of accessing identity information about perpetrators in other cases. The results could inform novel approaches for the future, which we hope will eventually be useful to the police.”
Between 1976 and 1986, the East Area Rapist, known later as the Original Night Stalker and the Golden State Killer, committed 12 murders, 45 rapes, and more than 120 residential burglaries in neighbourhoods across California.
Video: The FBI appealed again for information earlier this year (FBI video)
His victims ranged in age from 13 to 41 and included women home alone, women at home with their children, and husbands and wives.
Often sneaking into homes, he would tie up, rape and sometimes kill victims before ransacking their homes and stealing valuables.
The final murder victim, in 1986, was Janelle Lisa Cruz, 18, who was found raped and bludgeoned to death in her home in Irvine.
Although police have a DNA profile of the killer, they have not been able to match it to any known record.
His likely age means police could be running out of time to trace him. Today he is thought to be around 60 to 75 years old.
“Regardless of the amount of time that has passed, we never gave up on the investigation” said Sgt Paul Belli, the Sacramento County Sheriff’s Department detective assigned to the case, on launching a new appeal in June.
“This person ruined a great number of lives, and he should be held accountable.”
Dr Smith’s study involves asking people to take part in an online experiment, so that psychologists can use their collective responses to whittle down a more accurate representation of what the perpetrator might have looked like based on the sound of his voice.
Participants need to be aged over 18, as the recordings contain language some people may find disturbing.
Sgt Paul Belli, describes the search (FBI video)
Participants are asked to listen to the killer’s voice recordings and to view the facial sketches/composites, before judging them in terms of appearance and personality.
The researchers will draw correlations between the face and voice ratings for dimensions such as age, masculinity, height, weight, attractiveness and level of education – to try to get a better idea of which composite is likely to be the most accurate depiction.
A voicemail the killer left for a victim in 1978 (contains strong language)
Dr Smith was also behind the initial research earlier this year which suggested people were capable of building an accurate picture of someone just by hearing their voice.
Pictures of 18 faces and audio of 18 voices were presented to a test group of 47 participants, who were not told the faces and voices belonged to the same group of people.
Results showed people made similar judgements of how masculine, feminie, tall, healthy or over underweight they were – regardless of whether they just see their face, or only heard their voice.
Participants were also able to match the right face to the right voice 60 per cent of the time when asked if they belonged to the same person.
