A 25-year-old Alaska woman has been arrested for dousing her fiancée with gasoline while he slept on the couple's couch, setting him on fire and fleeing while he burned alive, according to police.

Gina Virgilio, a mother of a three-year-old boy, allegedly confessed to killing Michael Gonzales, 24, in East Anchorage on Friday morning.

On Sunday, the heroin and methamphetamine addict was arrested on charges of first-degree murder, arson, criminal mischief, reckless endangerment and assault.

Firefighters rushed to the scene of the fire on June 8, as the McCarrey Street blaze had destroyed the apartment. More than 15 other apartments were evacuated, according to the Anchorage Daily News.

But by 2:30 a.m., Mr Gonzalez was already dead.

Several other units in the building were also damaged and some neighbors were trapped inside their apartments, inhaling dangerous fumes until help arrived. They were hospitalized for smoke inhalation.

By that time, Virgilio had fled to nearby Wonder Park Elementary School and borrowed someone's cell phone to call her mother Michelle Virgilio, who picked her up.

Mrs Virgilio was awarded custody of Virgilio's son just days before the fire.

'Gina, she wouldn't hurt nobody, she wouldn't,' Mrs Virgilio said. 'Something caused her to do that.'

Mrs Virgilio said her daughter's addiction to heroin and methamphetamine made the couple's apartment a dangerous place for a child.

According to Facebook, Virgilio and Mr Gonzalez became engaged in April.

Virgilio's story about the events that led up to the fire rapidly unraveled as she told different versions to different people.

At first, Virgilio told her mother that Mr Gonzalez had been verbally abusive that night and was spitting gasoline at her. She claimed he used an aerosol shoe cleaner as a flame thrower and a fire broke out.

It was 'me or him' she said, and ran from the building.

Virgilio told the same story to police when they first questioned her, saying that Mr Gonzalez had been drinking with friends at the apartment late Thursday to celebrate his birthday.

She said that she left the party around 11 p.m. to buy gas, but officers found her broken-down vehicle with a notice on it stating it was to be towed on June 5.

Virgilio said that after she returned to the apartment, Mr Gonzalez began to sip gasoline from a red plastic cup and started spitting it onto the couch and carpet. She said he was 'acting crazy' and lit a piece of paper on fire.

She said she fled the apartment and called her mother.

Officials interviewed Virgilio all day before letting her leave, but when she returned to her mother's home, Mrs Virgilio demanded to know what really happened.

Mrs Virgilio said that her daughter told her that after she bought the gasoline, she returned to the apartment and found Mr Gonzalez asleep. She sat beside him for a while, looking at him.

Then she got up and started pouring the gasoline all around him, covering the carpet around her sleeping fiancee.

She walked to the door, lit a piece of paper on fire and tossed it into the apartment, Mrs Virgilio told police. Mr Gonzalez woke up and shouted 'Hot! Hot!', but Virgilio slammed the door and ran.

Virgilio was supposed to be arraigned on Sunday, but did not appear in court because she was on suicide watch, according to KTUU.

While being treated at Providence Hospital, Virgilio allegedly waved over a nurse and confessed. 'I did it, I killed Michael,' she said.

Virgilio was arraigned on Monday and held on $1million bail.

'Something was really wrong at that house,' Mrs Virgilio said.