A spokesman for Essex Police said:
"Evidence from fire scientists has indicated that the likely cause of the fire was malicious ignition.
"Detectives know that there was a burglary at the house on the same evening/early morning of the fire and are re-appealing for information and witnesses."
More top news
At least five people have suffered minor injuries but the cause of the blast is still unknown.
A songwriter from Harlesden who wrote a track for Beyonce's Lemonade album has been nominated for a Grammy Award.
Sadiq Khan issues the first 'very high' air quality alert since becoming Mayor