Four people have been arrested in connection with a house explosion in Lancashire in May, in which a young child died.
Two-year-old George Hinds was killed in the blast on Mallowdale Avenue on May 16. Two houses collapsed and a third was seriously damaged in the explosion.
George's parents and another man and woman required hospital treatment, Lancashire police said.
The force said a criminal investigation assisted by gas experts had identified the cause of the blast as a gas pipe which had been cut inside 20 Mallowdale Avenue.
A 44-year-old man and 51-year-old woman have been arrested on suspicion of manslaughter and have been released on bail pending further inquiries.
A 54-year-old man was arrested on suspicion of theft, criminal damage and abstracting electricity, while a 47-year-old man was arrested on suspicion of handling stolen goods. Both have been released under investigation.
With investigations continuing, police are also still hoping to speak to anyone who may have attended 20 Mallowdale Avenue in the days prior to the explosion.
Detective Chief Insp Jane Webb, of Lancashire Constabulary's Force Major Investigation Team, said: "These arrests mark a significant point in our investigation, however our enquiries are still ongoing.
"I would appeal to anyone who has any information that they think could assist with our investigation to please get in touch with us, specifically anyone who may have attended 20 Mallowdale in the days prior to the explosion.
"George's parents have been devastated by his death and the community of Heysham have been significantly affected by the incident. I would like to thank the community for their help throughout this investigation as well as those that have already come forward with information.
"Our focus remains on getting justice for George's family and loved ones, as well as those others affected by this incident. We will be pursuing all lines of enquiry to ensure we get the right outcome for those affected."
Anyone with any information is asked to contact police on 101 quoting log 0180 of May 16. They can also contact independent charity Crimestoppers on 0800 555 111.