UK triple murder: Post-mortem results due

Tania Clarence is being held after three of her children were found dead at the family's home.

Police forensic officers enter a house in New Malden, south London, on 23 April 2014 after three children were found dead. Picture: AFP.

LONDON - Post-mortem results are expected to be released later today in London revealing how three children were killed, allegedly by their South African mother.

The victims, a four-year-old girl and three-year-old twin boys, had spinal muscular atrophy (SMA) which left one in a wheelchair and the others unable to move.

The children were found dead at their home in New Malden, South London.

Their mother Tania has since been arrested in connection with their deaths.

Her husband Gary has returned home to the UK from a holiday in Cape Town with the couple's eldest child who is thought to not have any health problems.

Police have been very circumspect with what information they are revealing.

What is known is that authorities are continuing to question the 42-year-old graphic designer and said they were not looking for anyone else in connection with the incident.

SMA is a genetic disease that causes muscle weakness and progressive loss of movement.

It's reported a series of tests revealed the couple carried the disease and that three of their four children might not live into their teens.

The three youngest who were killed required constant care and a friend of the South African family said Tania was struggling to cope with her children's genetic condition.

Meanwhile, two women, thought to be relatives of the family, are reported to have called for help at a neighbour's house shortly after police arrived at the scene.

The women, one in her 30s and the other in her 50s, went next door and were described as "very, very upset" by the homeowner who let them in.