The blast caused two houses in Mallowdale Avenue, Heysham, to collapse and significantly damaged another at around 2.35am on Sunday, May 16.
Detectives said they now believe the cause of the explosion was a severed gas pipe inside 20 Mallowdale Avenue in a statement released today (May 24).
The enquiry into the explosion will now be treated as a criminal investigation as officers look into why the pipe was cut.
Det Chief Insp Jane Webb, of the Force Major Investigation Team, said: "My thoughts first and foremost remain with George's family and loved ones at this time, as well as those others affected by this incident.
"An incredible amount of work has been done at the scene in a relatively short space of time and as well as identifying the source of the explosion we have also managed to recover some items of George’s, which I know means a lot to his parents.
"Our focus now is on trying to establish how and why the pipe inside No. 20 came to be cut and those enquiries are complex and lengthy."
Tragically, George Arthur Hinds, aged two years and 10 months, died in the explosion.
His parents Vicky Studholme and Stephen Hinds, who were also injured, but not seriously, have paid tribute to their "beautiful little angel".
They said: "We are devastated at the loss of our beautiful George.
"He was so precious to us. We have no words to describe how we feel and just want time to ourselves to come to terms with what has happened. Our beautiful little angel grew his wings today."
Two other blast victims - a 44-year-old man and a 50-year-old woman - remain in hospital with "critical" injuries.
Police have now completed their forensic examination of the scene and it has been handed over to the local authority.
Det Chief Insp Jane Webb added: "I would like to thank the community for their help so far and I want to continue to appeal to anyone who may have information which could assist our investigation to come forward and contact us.
"Even if you think the information you have is insignificant or irrelevant please tell us and we can be the judge."
Anyone with any information should contact police on 101 or on the Major Incident Portal HERE, quoting log number 0180 of May 16.
Alternatively, independent charity Crimestoppers can be contacted anonymously on 0800 555 111 or online at crimestoppers-uk.org.
Support us and become a subscriber today. Enjoy unlimited access to local news, the latest football stories and new puzzles every day. With a digital subscription, you can see fewer ads, enjoy faster load times, and get access to exclusive newsletters and content. Click here to subscribe.