Molly Wigmore, 76, died in a fire at her home in Plymouth, Devon, on 19 October.
The BBC understands a member of Devon and Somerset Fire and Rescue Service's control room has been suspended.
Devon and Somerset Fire Service said it was a "challenging incident" and offered its condolences to the family.
More on the fire investigation, plus more Devon and Cornwall news
The first 999 call was made at 05:17 GMT, reporting a smoke alarm sounding and a smell of smoke from the property.
This should have led to firefighters being sent to the scene, but none had arrived by the time a second call was made at 06:44. A fire engine arrived at 06:50.
The house, in Sussex Road, is about a mile and a half from Camels Head Fire Station.
A coroner's inquest, supported by police, is expected to examine whether the delay in tackling the fire played a role in her death.
The fire service will also hold an internal investigation when the police inquiry has been completed.
A statement from the fire service said: "The crews involved dealt with an extremely challenging incident. This tragic death is now subject of a police investigation in support of the coroner.
"We would wish to offer the family of the deceased our deepest condolences."
The MP for the area, Oliver Colville said: "I will be writing to the fire brigade to ask them to explain exactly what happened and what we can do to make sure this doesn't happen again."
Devon and Cornwall Police confirmed an investigation is underway.
Tributes left at the house credit Ms Wigmore as being an "inspirational, kind, gentle and sweet lady".
She was a founding member of Plymouth Credit Union, according to former colleague Elizabeth Gray.
Ms Gray said: "She was a very hard worker and did it as voluntary. It's a very sad loss."
Police are investigating why it took more than an hour and a half for firefighters to get to a blaze in which a woman died, the BBC has learnt.