Paul Dennis. Photograph: Public Domain

A scientist at the University of East Anglia has been questioned by detectives ­investigating how controversial emails were leaked from the campus's climate research unit.

Norfolk police have interviewed and taken a formal statement from Paul Dennis, 54, another climate researcher who heads an adjacent laboratory.

The leaked emails from the head of the unit, Professor Phil Jones, surfaced just before the Copenhagen conference in December and caused a furore because they suggested that data which did not support theories of global warming was being deliberately withheld. Dennis denies leaking the material. But it is understood that his links with climate change sceptic bloggers in North America drew him to the attention of the investigating team, and have exposed rifts within the university's environmental science faculty.

Dennis refused to sign a petition in support of Jones when the scandal broke. He told friends he was one of several staff unwilling to put their names to the Met Office-inspired statement in support of the global warming camp, because "science isn't done by consensus".

University sources say the head of department, Professor Jacquie Burgess, received a letter from Dennis at the height of the email uproar, calling for more open release of data. He appears to have disapproved of the way Jones resisted FoI requests.

Dennis's own research, which dates fluctuating temperatures in ice cores stretching back thousands of years, does not support the more catastrophic current predictions of runaway global warming.

He has a history of contact with the American bloggers who bombarded Jones's unit with FoI requests, and were the first to receive the leaks. The ensuing global row led to Jones standing aside from his post. Last week he was rebuked by the Information Commissioner's office for apparent breaches of FoI rules.

One piece of information that led police to question Dennis was the discovery of emails between him and Stephen McIntyre, who runs a sceptic blog in Toronto called Climate Audit. Climate Audit was the first to receive an anonymous link to the leaked data. Dennis subsequently emailed McIntyre to alert him to a University of East Anglia (UAE) message confirming that a leak had occurred.

The scientist also had contact with Patrick Condon, an aeronautical engineer in Morris, Illinois, who runs a similar maths-oriented sceptic blog called Air Vent, and criticises "leftists" who promote global warming theories.

A third blogger with whom Dennis has posted is Anthony Watts, a weatherman for a California radio station who is involved in a sometimes vituperative sceptic blog called Watts Up with That. He has had a book published by the Heartland Institute, a denialist organisation which until 2006, received funding from ExxonMobil.

All three American bloggers, McIntyre, Condon and Watts, were initially sent links to the cache of CRU leaked material, via anonymous servers, on the same day, Tuesday 17 November.

McIntyre then received a message from Dennis in Norwich, where UEA is located. According to files obtained by police, he wrote: "Hi Steve, Yesterday we received the following email, sent to all staff in environmental sciences and the climatic research unit. I have no idea what stuff was collected or where it was posted, but interesting nonetheless!"

The attached message from Prof Alastair Grant, deputy head of department, said: "A large volume of files and emails from computers in ENV and CRU have been posted on to a website, apparently by climate change sceptics."

The university's move followed a tipoff from a Nasa climate scientist, Gavin Schmidt, in New York. Schmidt said his own blog, called Realclimate, had been temporarily taken over by a hacker posting a link to the university's internal emails.

Staff at the beleaguered environmental sciences department say they have been asked not to talk to the media. But Dennis has now posted an account of his police interview at a British website run by a sceptic accountant, Andrew Montford.

He told Montford's blog, called Bishop Hill: "They thought I might have some information on the basis that I had sent [Condon] a copy of a paper I had published on isotopes and climate at the southern end of the Antarctic Peninsula … and I had exchanged emails with Steve McIntyre over the leak/hack.

"Clearly they've trawled through the UEA mail server and checked for key words … The police left me very much with the impression that they were working on the theory that this was an outside hack and was done deliberately to disrupt Copenhagen."

Norfolk police have discounted tabloid stories of links to Russian intelligence, despite claims this week by the former government chief scientist Sir David King. He said only foreign intelligence agencies or US lobbyists had the resources to make the "highly sophisticated" selection of embarrassing phrases and correspondence dating back to 1996 in the leaks.

But a technical analysis by the Guardian shows the process could have been much more straightforward. The files were all in one place on a backup server, according to UEA, and all it took to sift them was a series of simple searches using keywords such as "Yamal" [the name of a controversial research project], "tree rings", or "Phil Jones". This would explain why many of the published emails and documents contain such keywords.

On at least two previous occasions, in 2008 and July 2009, data on the CRU ­servers turned out to be accidentally accessible to the probing bloggers – simply thanks to weak security.

The police have now moved on to a series of "very detailed" approaches to the overseas bloggers and members of their chat forums, asking if they had access to university passwords, and if they have any theories of their own.

"The police really don't know what happened," says Condon, who was emailed by investigators after Christmas. He told the Guardian: "It seems to me more like a prank than anything else."

• This article was amended on 8 February 2010. The original referred to Norwich University. This has been corrected.