Refugio Jimenez Jr and his wife Angelina have also been ordered to pay $1.78m (£1.41m) for the southern California wildfire that burned an area equivalent to twice the size of Oxford.

After a smoke machine ignited dry grass at the foot of the San Bernardino mountains on 5 September, the couple tried to douse the initial flames with bottled water.

But they couldn't stop the flames from spreading, which ultimately injured 13 people, forced the evacuation of hundreds and killed 39-year-old Charles Morton on 17 September.

"Resolving the case was never going to be a win," the district attorney Jason Anderson said, offering his condolences to Mr Morton's family.

"To the victims who lost so much, including their homes with valuables and memories, we understand those are intangibles can never be replaced."

Refugio pleaded guilty to one count of involuntary manslaughter and two counts of recklessly causing a fire to an inhabited structure - he will be jailed on 23 February.

His sentence includes two years of felony probation - a supervised alternative to jail essentially acting as a suspended sentence - and will also have 200 hours of community service to complete.

Angelina admitted to three misdemeanour counts of recklessly causing fire to the property of another and was sentenced to 400 hours of community service, with one year of summary probation, which is a less restrictive type of suspended sentence.

The US Forest Service is also suing the pyrotechnic device's manufacturers, distributors and sellers, as well as the couple, alleging the "smoke bombs" used were illegal and known to be defective.

Mike Scafiddi, Refugio's lawyer, said the couple has wanted to speak publicly about the fire, its impact on the community and Mr Morton's death but cannot because of the ongoing case.

"They have been praying for Mr Morton and his family every night since his death," he said.

"It has touched them profoundly."

He added his client had researched and tested the pyrotechnic device before setting it off that day, finding no problems online or during his test.

"It was unforeseeable in all minds," he said.

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Mr Scafiddi said the couple had not, contrary to what's been said publicly for years, hosted a gender-reveal party.

It was a photo shoot to discover the baby's gender with the couple, a few relatives and their children, he said.

"To infer that it was a gathering of multiple people with food and celebration is simply incorrect," he added.

"This was simply taking photographs in what was a beautiful backdrop."