Children are a source of joy. They bring a whole new kind of love into your life, and one can’t imagine life without them. Children are not things to be molded, they should be protected and taken care of.  Police have arrested a woman for the death of two sets of twin boys who died in a devastating house fire in south London.

The 27-year-old has been held on suspicion of child neglect of the twin boys aged three and four, the London Metropolitan Police said.

Fire crews were called to a mid-terrace house in Collingwood Road, Sutton, shortly before 7 pm on Thursday and found a “very well-developed” blaze, with the four boys inside, said Richard Mills, deputy commissioner of the London Fire Brigade.

He told reporters at the scene on Friday: “I can confirm that they are two sets of twins, ages four and ages three.”

Asked if anyone else was in the home, he said: “On arrival, there were four children in the house.”

According to Scotland Yard, the twins are said to be all related.

They were treated at the scene before being taken to two south London hospitals where they were pronounced dead.

In a statement on Friday morning, the force confirmed the arrest and said the woman remains in police custody.

Mr. Mills said firefighters in breathing apparatus entered the home, removed the four children, and gave them CPR.

The fire was under control by 8.36 pm and the cause is under investigation.

Speaking of the firefighters involved, he said: “Entering a building and rescuing life is always a very difficult place to be. The age of the children, the fact they are so young, will have a profound impact on them.”

Crews who attended are receiving counseling, he added.

London Fire Commissioner Andy Roe also earlier said the children’s deaths had “left everyone numb with profound sadness”.

Wreaths were being laid outside the police cordon on Collingwood Road on Friday morning, with a message on a bouquet that read: “Sleep well. Love grandpa.”

The Metropolitan Police said that the families of the children are aware and they will be provided with expert assistance.

At the time of this report, no one knows the cause of the fire at this early stage but will be investigated.