Police in Essex are speaking to two young people, seen throwing away a laptop bag on the night of a fatal fire.
It's been revealed the house in Harlow - where Sabah Usmani and her five children died - was burgled on the night of the blaze.
Officers think several items, including a laptop, were taken after the family had gone to bed but before the fire was discovered.
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In a wide-ranging Peston on Sunday interview, he said Parliament security needs reviewing and the PM's counter-terror strategy is flawed.
The terror attack carried out by Khalid Masood at Westminster that left four people dead lasted less than two minutes say police.
Two knives were found at the scene in Islington, North London, and the suspects fled on foot before being arrested.