UPDATE 1 p.m. Monday:

Alaska State Troopers say the fire victims have been tentatively identified as Becca White, 24, and Isaiah Parka, 22, both of Napakiak.

Original story:

Two prisoners died in their jail cells early Sunday when the Napakiak jail in Southwest Alaska went up in flames, the Alaska State Troopers said.

A jail guard was seriously injured trying to free the prisoners.

Troopers first received a report that the Napakiak jail was “fully engulfed in flames” at 1:27 a.m. on Sunday.

“It was reported that two jail guards were able to get out of the building; however, two prisoners who were inside the jail cells were not able to get free,” troopers wrote in an online report.

When the fire was extinguished, “two bodies were located at the scene,” troopers said.

One jail guard was seriously injured trying to free the prisoners and was flown out of the community by a medevac helicopter. He was hospitalized for injuries, troopers said.

A different guard “reported that the fire was a result of one of the prisoners setting fire to the mattress in their jail cell,” according to troopers.

Authorities have not yet identified the victims.

Napakiak is village of about 380 people southwest of Bethel, on the Kuskokwim River.

Many aspects of the fire remained under question as of Sunday night, including who operated the jail, what the victims were in custody for, whether the building was equipped with smoke detectors, and how materials to start a fire got into the holding cell.

In hubs like Bethel and Nome, regional jails are operated by the Alaska Department of Corrections. But in smaller villages, local governments may run the jail for short-term detention that are sometimes no more than a room with a lock on the door. Prisoners usually wait in holding cells until they can be transferred to jails in regional hubs.

The Alaska Correctional Officers Association said the jail guards involved were not union members.

Last summer, an extensive Association of Village Council Presidents survey of public safety facilities in the region found problems with Napakiak’s public safety building, including issues with the windows, door locks and exterior stairs, according to the report.

Photos included in the report showed a window with bars on it and an interior door that appeared to be closed with a piece of wood propped under the door handle.

It was not clear as of Sunday night whether the public safety building was where the fire had taken place.

As of Sunday afternoon, two troopers from Bethel, two fire marshals from Anchorage and an investigator with the Alaska Bureau of Investigation had traveled to Napakiak, said Megan Peters of the Alaska State Troopers.

None of the troopers, fire marshals or the investigator were available to answer questions, Peters said.

People in Napakiak contacted by the Daily News said they had been asked not to talk to media until the fire marshal was done investigating and families of the victims had been notified.

Sunday’s incident is not the first time a fire in a jail cell has killed an Alaska prisoner: In 1987, an Akiak teenager jailed for drinking set fire to a foam mattress at the city jail in a desperate bid to burn a hole through a wooden door, according to Daily News reports from the time.

At the time, state fire officials called for all inmates in jails both small and large to be given fire-retardant mattresses.