A prominent American doctor witnessed the murders of his wife and children during a brutal armed robbery at their home in a small affluent suburban town yesterday.

Dr William Petit Jr, a diabetes expert, was the only one of his family to survive the ordeal, which has shocked the residents of Cheshire, near New Haven, Connecticut.

His wife, Jennifer Hawke-Petit and two daughters, Hayley and Michaela, were killed, and their house set on fire.

Before committing their murders, two armed robbers were believed to have subjected the family to a reign of terror lasting hours which included one intruder taking a female member to a bank and ordering her to withdraw some money.

After bank clerks became suspicious and refused the transaction, the intruder brought the family member back to the house, and the robbers carried out their killings before setting the house on fire and destroying it.

Details of the injuries suffered by the dead family members are not yet clear as post-mortem results are still pending.

The men were captured as they tried to escape in a four-wheel drive despite ramming a number of police cars - who had arrived outside the house after being telephoned by the bank clerk - at around 10am yesterday. They were due to appear in court today.

Dr Petit, 50, was reported to be in a stable condition at St Mary's Hospital in the nearby town of Waterbury today after being beaten by the duo.

He is medical director of the Joslin Diabetes Centre at the Hospital of Central Connecticut and is well known in the area. "It is a shocking day for everyone. It's just beyond anyone's understanding," said Larry Tanner, president and chief executive of the hospital.

Dr Petit's wife of 22 years, Jennifer, 48, was co-director of the health centre at the Cheshire Academy, a local boarding school. "Everyone here is devastated. So, we are still in shock,'' said an academy spokeswoman, Colleen Reilly.

Philip Moore, director of communications at the school, added: "It's just a very difficult day here. We are just finding about it now. She was very good at educating kids about good health, not just taking care of them when they are not feeling well."

The small community of Cheshire today spoke of their shock at the family's ordeal. The mainly upper-middle class neighbourhood, which has one of the area's lowest crime-rates, features mainly colonial-style homes with well-kept lawns, and has a population of more than 29,000.

"In Cheshire we're not used to this type of event. It's probably going to reach right down to the core of the community,'' Michael Cruess, the town's police chief, said.

The Reverend Ronald A. Rising, a neighbour, said he has known the family for more than 10 years. "They're just a lovely family,'' he told AP. "It's just awful to think it would happen to a family like that in this community. You don't think about those things happening.''

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