UK police to question parents after ruling fire that killed 6 siblings was arson

Police say they will question the parents of six children killed in a house fire in an attempt to work out why their home was targeted in an arson attack.

Five of the siblings were killed Friday in the blaze in the central England city of Derby, while a sixth died in hospital Sunday as a result of his injuries.

Detectives confirmed Wednesday that the fire broke out after fuel was poured through the mail box on the front door of the house.

Two people arrested in the case were released without charge on Saturday.

Mick Philpott, the father of the children, told a news conference he rushed back into his home after the fire erupted in a thwarted rescue attempt.