A two-year-old boy who died in a suspected gas explosion in Oldham was watching television when the blast occurred next door, police said.
Jamie Heaton was killed in the blast in Buckley Street, Shaw. His neighbour Andrew Partington, 27, suffered severe burns and is unconscious in hospital.
Police are treating Jamie's death as suspicious and have "significant questions" for Mr Partington.
Jamie's family have paid tribute to their "happy, loving little boy".
In a statement they said he was a "precious son" to Michelle and Kenny and a loving little brother to Jodie and Jack.
"Jamie's life was full of laughter," they said.
"He loved going to preschool, playing with sand and water and going to the park. He touched the hearts of all who knew him and will be missed by all."
Detectives are investigating the cause of the blast, which happened at 11:15 BST on Tuesday, and are waiting to question Mr Partington.
Police said he was in a serious but stable condition in Wythenshawe Hospital.
National Grid has said the blast was not caused by a gas pipe leak.
Assistant Chief Constable Steve Heywood, from Greater Manchester Police, said: "We have had some information to suggest it may not be accidental so we are treating it as a suspicious death and therefore a homicide investigation is being undertaken."
Police are investigating reports of a domestic argument involving the injured man on Monday evening, although this was not reported to police at the time.
Mr Heywood said: "We have not made any arrests but we have a significant number of witnesses that we want to interview.
"At this time, I would not say we have an exact cause for the fire or an exact reason for why this happened but that will form part of this investigation."
National Grid said there was a report of a "gas escape" at 10:40 BST in the Edmund Street and Buckley Street area, which was shortly followed by another call to report that there had been an explosion.
The company has now confirmed the blast was not caused by a leak from its gas distribution pipes.
It said: "National Grid has not been able to gain access to carry out checks on internal pipes, meters and gas appliances.
"Greater Manchester Police has now taken control of the site and are treating it as a crime scene."
Mr Heywood said it was only by chance that Jamie's mother was not in the house when the blast happened.
"The victim, Jamie, was in the house, we believe the front room, watching TV and his mother had just slipped out into the back yard, hanging out washing," he said.
"What that mother must be going through must be unbelievable, so our hearts go out to her."
House numbers 7, 9 and 11 were destroyed in Tuesday morning's explosion and several other homes were also damaged.
The scene is expected to remain cordoned off for several days.
A large number of other houses remain within the police cordon and need to be examined by structural engineers before residents are allowed to return.
The scene was described as "catastrophic" by Greater Manchester Fire and Rescue Service's station manager Dean Nankivell. He said gas was a likely cause of the blast.
Mr Heywood compared the scene to something like the IRA's bombing of Manchester.
"This looks like there has been a bomb. The devastation is absolutely tremendous. Our thoughts go out to those families that have been displaced."
Police said officers were at the scene "within moments" of the blast as they were on patrol in the Shaw area when they heard a loud explosion.
They searched some of the houses damaged in the blast and Jamie's body was found inside.
Jackie Hunter, who lives six doors down from the explosion, said she felt her house lift up.
She said: "I jumped up, my front door had gone in, so I ran out and dialled 999.
"It was just so frightening, the noise was horrendous, I've got nothing at the moment, just the clothes I'm currently stood in."
Oldham Council set up a rest centre at Crompton House School in Rochdale Road for up to 80 residents removed from their homes.
It has opened the Oldham Distress Fund, into which people can make donations to residents affected through the council's website .
People can also contribute to the fund at the tills of the Debenhams store in Oldham town centre.
A relief fund has also been set up by the charity Forever Manchester on behalf of Greater Manchester local authorities.
A Red Cross spokesman said nobody stayed at the rest centre on Tuesday night, with people choosing to go to hotels or stay with relatives.
Councillor Jean Stretton, from Oldham Council, said the next immediate task was to assess the extent of the damage to properties which have not been completely destroyed.
She said: "There will be people who will not be going back, more [properties] could be unsafe, so will either be demolished or repaired.
"What we are doing is looking to provide people with some financial support, we are looking to support them with insurance claims but the council will do what needs to be done."
She added: "In the face of such adversity everyone has pulled together in a fantastic community effort."
Greater Manchester Fire and Rescue Service volunteers have been helping to rescue pets from homes in the affected area.
Several cats and kittens, a handful of dogs and rabbits, three hamsters and a terrapin were among the animals rescued.
Properties directly inside the inner cordon were still deemed unsafe to enter.