The former partner of Olivia Newton-John, who was believed to have drowned at sea nearly four years ago, staged his own disappearance, private U.S. investigators have claimed.

Patrick McDermott is said to be travelling along the Mexican and South America coastline under an alias to avoid paying debts and enable his teenage son to cash in on a $151,000 insurance policy.

McDermott was 48 years old when he disappeared after boarding a fishing charter boat called The Freedom in California in June 2005.

U.S. Coast Guard officials concluded that the cameraman had most likely drowned in a boating tragedy - which Newton-John, his parter of eight years, has always accepted.

But suspicion remained over McDermott's disappearance after it emerged he filed for bankruptcy before his disappearance.

He also owed thousands of dollars in child support payments to his ex-wife.

The show hired a private investigators agency in March 2007 to find McDermott and now believe they are getting close.

'He's alive - there's no doubt in my mind, this guy's alive,' lead investigator Philip Klein told the programme.

'Maybe in his mind if he stages his death, the insurance policy will pay off his debts and he can leave his child a gift by pretending he's dead.'

Klein claims that McDermott's life insurance policy 'is in full force and effect. The premiums have been paid every month. There has also been an inquiry by a person or persons in an attempt to possibly file a claim on the insurance money.'

Klein's agency set up a website called findpatrickmcdermott.com.

But it was actually a ruse to find McDermott by showing investigators the locations of people logging on to the site.

Klein began tracking hits from what he believes was a boat travelling along the Mexican coastline as far as South America.

'Sayulita, Mexico, is where many of the hits were coming from,' Klein said.

(read more at the UK Daily Mail)