It emerged yesterday that Christopher Foster's 15-year-old daughter may have been chatting to friends online in the early hours of the morning before the inferno destroyed her family’s sprawling Georgian country home.

Kirstie Foster was thought to have been on a social networking site when she was interrupted, possibly by a power cut at 1am, three hours before the blaze. Last night police were at the house hunting for the remains of the girl and her parents.

Kirstie, a student at the £16,500-a-year Ellesmere College in Shropshire, is believed to have been an enthusiastic member of the teenage-orientated Bebo network, where she swapped upbeat messages with her pals.

The family home of the missing millionaire businessman Christopher Foster has begun to give up its macabre secrets but it will be a slow process. At one point forensic science searchers sifting through the rubble of Osbaston House, in the village of Maesbrook, near Oswestry, were forced to retreat by tumbling debris.

Police still do not know whether the bodies of Mr Foster, 50, his wife, Jillian, 49, or Kirstie, lie beneath the blackened masonry. They have said that the search could take several weeks.

Four days after the investigation began into the deliberate destruction of the £1.25 million property in the heart of the commuter belt, the location resembles the opening scene of a particularly extravagant Inspector Lynley mystery featuring foul play at the end of a grand gravel drive. So far there is little plot development. Only the main character, a businessman with an extravagant lifestyle and a host of money worries, is taking shape against the smouldering cinders.

Mr Foster’s friends in Maesbrook, car dealers and property developers and those he joined on pheasant shoots or fishing trips along the River Morda, have retreated behind their security gates. The family left a friend’s barbecue, apparently relaxed and happy, at about 8.30pm on Bank Holiday Monday. At 4am fire broke out in the main house, stables and kennels.

Yesterday a convoy of police vehicles moved on to the site where structural engineers had worked to make it safe to search.

Three horses found dead at the scene have been examined and officers were awaiting the postmortem results.

The charred remains of the family’s pet dogs were also found. A large horsebox has been removed for scientific tests.

Human tissue may not be apparent to the naked eye but can be detected by scientific analysis. Material has to be laboriously tagged and taken away for examination.

When Mr Foster’s limited company, Ulva, which supplied insulation to oil rigs, went into liquidation last year it faced legal action from one supplier and owed £800,000 tax. The Court of Appeal described Mr Foster as “someone not to be trusted”.

Land Registry documents reveal that the liquidators had made an interim charge on the family home, which could have opened the way for repossession. There is speculation among business associates and villagers that Mr Foster “flipped” when his country-gentleman lifestyle appeared to be slipping away.

Terence Baines, a former director of Ulva, said: “He was an ordinary business salesman, running a company, and a family man. He was just an ordinary everyday chap, well dressed, a good businessman.”

Anne Giddings, 57, Mrs Foster’s sister, who lives in Perton, near Wolverhampton, said: “We are devastated. This just does not happen to your own family. It is like something you see on television.”

Kirstie’s schoolfriends said that she was popular and had a passion for horse riding. Her boyfriend, who is understood to live near Wolverhampton, has been described as deeply upset by developments. One 16-year-old pupil, in the year above Kirstie at Ellesmere, said: “There is no one who disliked her. Everyone got along with her. She had no enemies.”

Brendan Wignall, head teacher at the independent school in north Shropshire, said: “Kirstie is a charming, popular and hard-working girl with many friends, all of whom are hoping that she and her family will be found safe and well.”

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