A RETIRED electrical engineer has unravelled the mystery behind the Oxfordshire locations in his favourite TV detective series.

Chris Behan, from Adderbury, spent nearly a year travelling around quaint villages putting together a book on Midsomer Murders.

The drama is set in the fictional county of Midsomer which has a notoriously high murder rate, keeping actor John Nettles – who played Chief Inspector Tom Barnaby – busy for 14 years.

But the TV series, which has been on our screens since 1997, is filmed in Oxfordshire.

Many towns and villages take a starring role in the series, with Wallingford playing the role of county town Causton.

Other locations include Thame, Warborough, Islip, Nettlebed, Dorchester and Henley.

And the 74-year-old spent 2011 carrying out his own thorough investigation.

He said: “I travelled around Oxfordshire and the Chilterns and I must have taken around 3,500 photographs.

“My aim in the book was to give a reflection on the beautiful countryside the programme is set in and relate it to an episode of Midsomer Murders.”

Mr Behan’s book, Exploring Midsomer, includes nearly 200 photographs from his travels and is divided into chapters which make it easy for people to visit them Villages and towns are grouped by how close together.

But Mr Behan admitted: “I never intended to write a book. “I really enjoy watching Midsomer Murders and I have been watching it since day one. I know the TV series back to front now.

“Often I get asked whether I will go on Mastermind but I don’t think my knowledge of Midsomer Murders is that good.”

The book was born when publishing company The History Press offered him the chance to pitch some of his ideas to them after they had accidentally sent one of his submitted pictures to Oxford Mail sister paper The Oxford Times, and it was published Two years later the company has published his book.

The book, priced at £12.99 goes on sale on Saturday, June 30.