In relation to the tragedy, Dr Gerard Bailes, a consultant forensic psychologist at the Norvic Clinic in Norwich, Norfolk, said: "People always ask `How could someone do a thing like that?' But it is likely they would be suffering from a mental disturbance, perhaps even psychosis.
"If you look for a reason, it would only be found in that person's thinking at the time. It could be they believed their situation was hopeless, and the children would be better off dead than without them.
"There is always the option that it is revenge, getting their own back on a spouse. But even with that, the motivation is in themselves, they are cutting themselves off from reality."
He also warned against friends and relatives thinking they could have averted the tragedy. "Hindsight is a very exact science. It is very difficult for people to convince themselves they couldn't have done anything about it."
Ms Julia Cole from the marriage guidance group Relate said such cases, which were often connected with family break-up, showed the emotional impact of such situations.
She said: "People should not be blase about things like divorce particularly if there are children involved."
"People should realise, there is no such thing as an ordinary divorce," she said.