A father came home from work to discover that his wife had murdered their two young sons then hanged herself.

Richard Talby found the bodies of his wife, Susan, and sons Joseph, 4, and Paul, 2, at his home in Peterborough on Thursday evening. The boys are thought to have been suffocated or strangled. Mr Talby’s father, John Talby, told The Times that Mrs Talby had suffered from postnatal depression after her younger son was born, but appeared to have overcome it.

“We saw her last week, on Thursday, and she seemed perfectly normal. Paul was 2½ [years old]. He was talking and walking, was soon to be out of nappies and about to go to playgroup, so the situation was becoming easier for her. Joseph had started school and was about to celebrate his fifth birthday.

“Richard found the scene when he came back from a business trip to Reading yesterday. It must have been absolutely terrible.”

Speaking from his home in Bourne, near Peterborough, John Talby explained that his son and daughter-in-law were comfortably off and appeared happy. He went on: “Richard is a rep for a polymers plastics company and was in the course of leaving his job this week to start another job in the same line, so he was very happy. His career was progressing.

“Susan was at home with the children during the week and worked at Next in Peterborough every Sunday. They had no money worries and seemed to be all right.”

Richard Talby’s mother, Janice, added: “We are absolutely devastated. We have no idea why this happened, but it has left us brokenhearted. We have lost our daughter-in-law and our grandchildren and we don’t know how we will come to terms with it. We are just supporting Richard, who is in Peterborough at the moment with the police family liaison officer.”

The family’s semidetached house in Coventry Close, Werrington, a neat cul-de-sac of modern houses on the edge of Peterborough, was cordoned off yesterday for scientific examination. Police also conducted house-to-house inquiries.

Cambridgeshire police said they were treating the boys’ deaths as murder and that of Mrs Talby, 41, as “unexplained”. Postmortem examinations were under way.

Joseph was a pupil at Werrington primary school. Staff held a special assembly to tell the 400 children about the death. Ben Wilding, the head teacher, said: “Joseph was a delightful boy who had made a big impression on his classmates and everyone who knew him. He will be desperately missed. Trained counsellors have been on site and they will remain so at the end of the day. We shall be keeping a very watchful eye on all our school community and call upon specialist support as required.”

Richard Talby is believed to be a keen runner who has competed in the Great Eastern Run and the Peterborough Half-Marathon in 2003.

This week, the National Institute for Health and Clinical Excellence (NICE) issued guidance to the NHS urging doctors and midwives to do more to identify women at risk of postnatal depression. As many as one in seven suffers a mental health disorder at some point during pregnancy or after the birth. However, experts believe that the number of sufferers who have a diagnosis could be as low as 30 per cent.

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