A private detective accused of exploiting the hunt for Madeleine McCann to fund his lavish lifestyle has been found dead.

Kevin Halligen, 56, gained notoriety when his firm Oakley International was used by the toddler’s parents to help search for their missing daughter.

His Washington-based company received about £300,000 of cash donated by the public after Madeleine vanished from an Algarve resort in May 2007 at the age of three.

He was later forced to deny claims the money was actually siphoned off to pay for first-class travel, luxury hotel suites, a chauffeur and a mansion in Virginia, US.

Kevin Halligen has been found dead (Adrian Gatton/PA)
Kevin Halligen has been found dead (Adrian Gatton/PA)

Adrian Gatton, a TV director and investigative journalist, who made a documentary with Halligen in 2014 for Channel 5 – The McCanns and the Conman – and who knew Halligen well, confirmed to the Press Association that he died last Monday, having sunk into alcohol addiction.

He said: “Although his death is certainly not foul play, as has been suggested, there are certainly a lot of people who wished him ill. But he was also unique. I knew chapter and verse about his life and career, but my interest was really to try and get to the bottom of why he did what he did.

“My understanding is that he was found dead on Monday night. There was blood around the house, probably caused by previous falls when he was either drunk or blacking out.

“Halligen was increasingly shambolic and these blood stains hadn’t been cleared up. His house was full of empty drink bottles. A lot of people wished him ill but his death is almost certainly related to alcoholism.”

Surrey Police said the death was currently being treated as “unexplained”.

A spokesman said: “We were called to an address in Cobbett Hill Road, Normandy, on Monday following a report of a man in his 50s having been taken unwell, who subsequently died. The death is being treated as unexplained and a file will be passed to the coroner’s office in due course.”

The McCanns used the Irish national’s firm for around six months to look for their missing daughter. The £500,000 contract saw the firm hire private detectives, set up a hotline and process information.

The McCanns terminated the arrangement without paying the full fees because Halligen, from Surrey, apparently failed to fulfil certain agreements.

He was then extradited to the US in 2012 to face charges over an unrelated £1.3 million con, to which he pleaded guilty in 2013.

Dutch company Trafigura were targeted in the scam, being told by Halligen that he needed funds to secure the release of two business executives who were arrested in the Ivory Coast.

In an interview for a 2014 Channel 5 documentary, Halligen denied claims he misused money raised to find Madeleine.

He said: “It is gross distortion of what was actually happening. The print media in particular took this line that really nothing was being done, I was living the high life on the proceeds of the McCann case. Trust me, I didn’t buy so much as a new suit. The money, all of it, is fully accountable.”