An explosion that killed a two-year-old boy was caused by a gas pipe which had been cut inside a neighbour's home, police say.
Toddler George Arthur Hinds was killed in the explosion after the blast in Mallowdale Avenue, Heysham. He was two months short of his third birthday.
Four others were hospitalised, including George's parents Vicky Studholme and Stephen Hinds, who have since been discharged.
A criminal investigation has now been launched after Lancashire Police detectives, assisted by gas experts, carried out fingertip searches of the scene - revealing the explosion was caused by a gas pipe which had been cut inside a neighbouring house.
Enquiries are now ongoing into how, and why, the pipe was cut, which police say will take "some considerable time".
Detective 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."
The Detective Chief Inspector added: “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.
“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."
Emergency services were called to the scene on Sunday 16 May, where they found two houses collapsed with serious damage to a third property.
Ten fire crews and six ambulances were among those sent to the scene at around 2.30am on Sunday, with firefighters searching the collapsed property.
Two other people - a man aged 44 and a woman aged 50 believed to be neighbours - remain in hospital with injuries described as critical.
In a statement, George's parents paid tribute to their son: "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."
Gas supplier Cadent, earlier said following its own investigations its mains and pipes 'did not contribute to or cause' the explosion.
A nearby pub, the Hurley Flyer has already helped to raise more than £51,000 for families affected by the explosion on a GoFundMe page.
Anyone with any information should contact police on 101 quoting log 0180 of May 16th or on the Major Incident Portal.
Alternatively contact independent charity Crimestoppers on 0800 555 111.