• Adam Lanza
    © Agence France-Presse/Getty Images
    Sandy Hook Elementary School shooter Adam Lanza at an unknown location in 2005 - Lanza's DNA is being examined for any evidence that could shed light on his actions that day
    The study will be the first one of its kind and will evaluate any genetic evidence for the mass killing of 20 first graders, six members of staff at Sandy Hook Elementary School and his own mother.
Scientists have been asked to study the DNA of Newtown school killer Adam Lanza to see if has an 'evil' gene that led him to carry out the massacre.

The study, which will look at any abnormalities or mutations in his individual DNA, is believed to be the first of its kind ever carried out on a mass murderer.

Lanza slaughtered 20 children and six adults in one of America's worst ever school shootings on December 14, 2012.

The 20 year old also shot dead his mother Nancy before taking his own life as police closed in on him at the Sandy Hook elementary school in Connecticut.

The massacre prompted President Obama to look into new gun controls and banning assault rifles such as AR-15 Bushmaster used by Lanza in his rampage.

The study of the killer's DNA has been ordered by Connecticut Medical Examiner H. Wayne Carver who carried out the post mortems on all the victims.

He has contacted geneticists at University of Connecticut's to conduct the study.

Geneticists said they are likely looking at Lanza's DNA to detect a mutation or abnormality that could increase the risk of aggressive or violent behavior.

They could analyse Lanza's entire genome in great detail and try to find any unexpected mutations.

Arthur Beaudet, a professor at Baylor College of Medicine, said the University of Connecticut geneticists are most likely trying to 'detect clear abnormalities of what we would call a mutation in a gene'.

He added: 'Or gene abnormalities and there are some abnormalities that are related to aggressive behavior.

'They might look for mutations that might be associated with mental illnesses and ones that might also increase the risk for violence.

Beaudet, who is also the chairman of Baylor College of Medicine's department of molecular and human genetics in Houston, Texas said geneticists should be doing this type of research because there are 'some mutations that are known to be associated with at least aggressive behavior if not violent behavior.'

'I don't think any one of these mutations would explain all of (the mass shooters), but some of them would have mutations that might be causing both schizophrenia and related schizophrenia violent behavior,' Beaudet said.

'I think we could learn more about it and we should learn more about it.'

Beaudet,who is chairman of the Baylor College department of molecular and human genetics, said studying the genes of murderers is controversial because there is a risk that those with similar genetic characteristics could possibly be discriminated against or stigmatized.

But he said the research into Lanza would be helpful even if only a "fraction" may have the abnormality or mutation.

'Not all of these people will have identifiable genetic abnormalities,' Beaudet told ABC News in America.

'By studying genetic abnormalities we can learn more about conditions better and who is at risk and what might be dramatic treatments,' Beaudet said, adding if the gene abnormality is defined the 'treatment to stop' other mass shootings or 'decrease the risk is much approved.'

Police have so far failed to find a motive for Lanza going on the deadly rampage.

Although known to be shy and social inept Lanza had not shown any violent streak although he was known to spend hours in the basement of his home playing violent video games.

His mental condition may also have been affected by his 52 year old mum who was a 'prepper' and had stockpiled food and guns in readiness for a disaster.

A six year old British boy, Dylan Hockley, was among the young victims gunned down the week before Christmas.