Harbhajan Singh Rooprai was inside his home when 27-year-old Tyrone Jacobs allegedly set his home on fire, causing flames to be ripped through the terraced house in Forest Gate.
Rooprai died from burns and inhalation of fumes after he was found on the ground floor of the property.
Twenty-one firefighters and four engines tackled the blaze, which was brought under control after two-and-a-half hours.
Four people had managed to escape from the house before firefighters arrived.
More From This Section
Another 32-year-old woman arrested on suspicion of murder has been bailed until mid-February.
Detective Chief Inspector Steve McCabe said: "Mr Rooprai's family have been left devastated by what has happened and are struggling to come to terms with the loss."
Rooprai's relative Harjit said, "Words cannot express the pain and anguish of our family and friends have endured since the loss of our dear and loving uncle on Christmas Day".