The City superwoman and the hunt for little Snooks

The investigation into the kidnap of seven-year-old London schoolgirl Reigh Boss has uncovered a baffling story about her parents' relationship and the strange life of her father, Clark Rockefeller. As police across the United States hunted for him and the abducted child today, the details of Rockefeller's enigmatic past began to unfold.

Reigh's mother Sandra, a partner with the global management consultancy McKinsey and Co and described as "a City superwoman", was sitting in a hotel room waiting for news but so far, every attempt to locate Reigh and her runaway father has failed. It looked as if Rockefeller had deliberately laid a false trail to confuse his pursuers and the clues the police have are raising more questions than answers.

The most perplexing question of all is the one at the heart of the kidnap mystery: how did a man like Clark Rockefeller manage to become part of the life of a woman like Sandra Boss?

She was one of the top people at McKinsey's office in Boston, Massachusetts. She and Rockefeller lived with their daughter in a £1.3 million brownstone house on Pinckney Street, in the upscale Beacon Hill district. Former presidential candidate John Kerry was a neighbour.

The marriage started to go wrong, for reasons that will become clear, and Ms Boss filed for divorce. She then moved to London with Reigh. At 41, her career moved into overdrive. She is one of the top people at McKinsey, one of the City's most prestigious firms, and an acknowledged expert on banking and securities. She is also an adviser to the Metropolitan Museum of Art in New York and Boston's Museum of Fine Arts.

She flew to Boston last week with Reigh - always known by the name of her favourite storybook character, Snooks - to comply with a custody order that allowed Rockefeller visits with his child. As father and daughter strolled in the sunshine on Beacon Hill on Sunday afternoon, under the supervision of a male social worker, Rockefeller snatched the child, bundled her into a waiting vehicle and sped off.

HE HEADED for New York, where his romance with Reigh's mother began. He and Sandra Boss met in the early 1990s when she was already a high-flyer. She came from a professional family in Washington State and had graduated from Stanford University before going on to take a business degree at Harvard. Contemporaries described her as "beautiful and brilliant".

By her late 20s she was on Wall Street, working for Merrill Lynch, the investment bank. She was passionate about the arts and had a wide circle of friends among whom appeared the rather odd looking figure of Clark Rockefeller.

Small of stature, with receding redblond hair, and nearly 10 years older than Sandra, he did not seem the kind of beau her friends expected. One described him as "a character". He wore bow ties, a Yale university baseball cap and seemed to be fairly affluent. He attended church with the old money crowd at St Thomas's on Fifth Avenue and was frequently seen at the Metropolitan and Knickerbocker Clubs.

"Everyone called him Mr Rockefeller," one friend said. "But I don't think anyone in his life knew - including Sandra - what was real and what wasn't. People would get interested and look into it, but they'd never get far." Rockefeller did not actually say he was part of the legendary Rockefeller oil dynasty but he did nothing to dispel the idea. He used to fiddle with an old pocketknife on which a name was engraved: Nelson Rockefeller. He indicated he had independent means and occasionally dropped hints that he was also involved in investment management.

There was a story in New York that one of Sandra's relatives became suspicious of him and did a little digging. Rockefeller used to boast about his time at Yale but Sandra's family found incontrovertible evidence that he had never been there. If the discovery caused a crisis, it quickly passed. He and Sandra were married on Nantucket Island, in 1994.

She moved swiftly up the career ladder and took a highly-paid job at McKinsey in Boston. While they maintained a house in the city, they also had a home in Cornish, New Hampshire.

Cornish is a small community and the Rockefellers became part of it, although some had deep reservations about Clark Rockefeller. "He was a wacko," Mike Monette, the town's former fire chief said.

Cornish is accustomed to eccentrics - the ¸ber-recluse JD Salinger is a long-term resident - but Clark Rockefeller grated on some. He and Sandra bought Doveridge, a historic house that had been the home of a famous American jurist, and began a programme of restoration. Rockefeller would ride around town on his Skegway, the electric personal transporter that was briefly fashionable, usually wearing a Yale baseball cap and the preppy uniform of polo shirt, chinos and deck shoes without socks.

Residents say he was paranoid about security. He bought three old police cars and parked them on his drive with signs on them that read Doveridge Security. Locals said it was an attempt to suggest the house had special protection but it convinced no one. When an author asked to photograph Doveridge for a book project, Rockefeller refused. He said he was engaged in secret work for the Pentagon and could not be exposed to any publicity. To others he said he was a mathematician, or physicist.

Some took an active dislike to Rockefeller. A neighbour in Boston described him as "a phoney". One said: "He used to complain to me that his chef was cooking too much fancy food. 'I've had just about enough confit de canard,' he'd say." To others he boasted of a fabulous art collection, a fleet of vintage cars and he hinted at vast reserves of old wealth. When someone confronted him directly about whether he was a member of the Rockefeller family, he replied: "Maybe I am, maybe I'm not."

But he was also capable of great charm. Emily Miller, 19, a Cornish resident, was Reigh's babysitter. She said: "When people called her Reigh she would say: 'No, my name is Snooks.' Mr Rockefeller would say: 'This is my daughter. She wants to be called Snooks.'"

He built a playground in the grounds of their home and according to Ms Miller he doted on Reigh. "I really like working with him," she said. "He was great with Snooks. I don't believe he would ever do anything to harm her."

A local restaurateur described Rockefeller as "flamboyant" and said he liked to give the impression he had plenty of money.

But whose money was it? In Boston, Rockefeller led the life of a gentleman about town, joining the exclusive Algonquin Club and becoming one of its directors. But his real life, according to neighbours, was that of house husband. One said he was a "Mr Mom" and he took care of household matters while Sandra pursued her high-powered job.

It could have been an ideal arrangement, given Rockefeller's delight in looking after his child, but things began to go wrong. According to evidence surrounding their divorce - which has since been closed to public scrutiny - Sandra discovered her husband had a string of aliases. She found he had variously called himself JP Clark Rockefeller, James Frederick, Clark Mill Rockefeller and Michael Brown.

Clark Rockefeller was his most consistent name, but he also asked people to call him Michael. Michael Clark Rockefeller was indeed a member of the family behind Standard Oil. He was the youngest son of Nelson Rockefeller, who disappeared on an expedition to the Asmat jungle in New Guinea in 1961. Investigators believe the fugitive Clark Rockefeller was born in 1960.

Did he assume the identity of the missing man? No one knows for sure. So far, the police have been unable to find a social security number for him and they cannot place his true identity. They believe he has never held a driving licence.

All these facts slowly became clear to Sandra Boss. To outsiders, it seemed she was the charming and clever wife of a man from an old American family whose eccentricities she chose to overlook. But as their marriage foundered , she was becoming increasingly desperate and accused him of duping her.

And as he passed himself off as a millionaire, it was she who was providing the money. In 2004, Cornish residents launched an appeal to save the town's historic Trinity church, one of the oldest in America. Rockefeller stepped forward at a public meeting and grandiosely offered $110,000 (then worth around £65,000). It made Cornish residents think that he really did have money but the Evening Standard has learned that the funds were provided by Ms Boss, who created a trust to preserve the church.

Ms Boss is also the owner of Doveridge, the couple's home in Cornish. The house is now being offered for sale after it was valued at $774,000 (£390,360).

John Gregg, a local newspaper reporter, asked Ms Boss about Rockefeller. She replied: "I don't really want to respond to that. I'm doing a lot in the community to preserve the church and I would like to have my personal life kept private."

That now seems impossible. The search for Rockefeller is now an international manhunt. As the FBI issued pictures of him and Reigh and photographs of dresses he is believed to have bought for her before their escape, there was only one sighting, in Delaware. Before the police could move in they vanished.

NOW it seems clear that Rockefeller had been planning the kidnap for some time. He told friends he had bought a 72-foot yacht, Serenity, and said he was planning to sail it to the Bahamas, or South America. When police were told this, they sent up a spotter plane and alerted the coastguard and yacht harbours. The first two days of the hunt were concentrated on finding the yacht.

They now believe it probably doesn't exist and that it was a red herring deliberately placed to throw them off Rockefeller's trail.

This theory was reinforced by something he said to a friend, Aileen Ang, whom he knew from Boston. He paid Ms Ang $500 to drive him and Reigh to Grand Central station in New York, having told her that he had custody of his daughter. Ms Ang said on the Boston radio station WBZ: "She [Reigh] was happy playing in the back. She was actually saying 'I love you too much daddy'. He would respond: 'I love you even more.' So it was kind of, I thought, normal."

When Ms Ang dropped them off, Rockeffeller made a point of asking her if she wanted to join him and his daughter on a six-month yacht cruise. When she declined, he said: "Are you sure?"

Investigators believe this was to leave Ms Ang with a firm impression he was taking Reigh abroad on a yacht.

But while their spotter plane was searching America's eastern seaboard, they now believe, the mysterious "Mr Rockefeller" was probably heading in the opposite direction.