Norfolk Police say no criminal charges will be brought despite evidence of a "sophisticated and orchestrated" hacking attack on University of East Anglia's computers. An inquiry was launched after hacked emails from the University of East Anglia's Climatic Research Unit (CRU) were leaked online in 2009 before crunch UN climate talks.
Climate change sceptics claimed the emails showed scientists manipulating data to support a theory of man-made global warming, but a series of reviews later cleared researchers at the unit of any scientific impropriety.
On Wednesday, the force said that the investigation had concluded the breach was "the result of a sophisticated and carefully orchestrated attack on the CRU's data files, carried out remotely via the internet". But a statement added that there would be no criminal proceedings.
Detective Chief Superintendent Julian Gregory said: "Despite detailed and comprehensive enquiries, supported by experts in this field, the complex nature of this investigation means that we do not have a realistic prospect of identifying the offender or offenders and launching criminal proceedings within the time constraints imposed by law."
He added that there was nothing to suggest that anyone working at or associated with the university was involved in the crime.
Professor Edward Acton, vice-chancellor of the University of East Anglia, said he was disappointed that those responsible for the crime would not be brought to justice.