Firefighters rushed into the blaze and found her in her bedroom, not breathing. Fire crews carried her from the house and managed to resuscitate her.
She has remained in critical condition at El Centro Regional Medical Center since then, suffering from severe smoke inhalation.
Her great-grandson was not injured and is staying with other family members.
Fire officials said there were several points of origin on the exterior of the house where the fire was ignited, leading authorities to conclude the cause was arson.
Authorities have conducted interviews and are continuing to follow leads, but there aren't many, according to El Centro police Lt. Tim Blankenship.
Still, he said the investigation will continue.
On Friday, a reporter visited the remains of the home Hoyas had lived in for more than two decades. It is a small wooden house, painted in bright yellow.
At the back of the home, nothing remains but a charred frame. The front of the house remains intact, but burn marks indicate the damage inside.
Friends and neighbors said they are praying for Hoyas, adding she is a good person who did not deserve to be the victim of such a crime.
All those interviewed declined to give their names.
One neighbor said she would chat with Hoyas on a regular basis.
"For me, this is weird," said the neighbor. "She is a really nice person. She would talk to everybody. She had a lot of friends."
One such friend, who lives close to Hoyas, said she is concerned for her friend.
"I think my best friend has gone away," said the woman, who added Hoyas is a "very good woman."
Two other neighbors, who said they have been friends with Hoyas since they moved into the neighborhood, walked by the house Friday afternoon to see the damage.
One neighbor, pointing to a number of plants in front of the house — all untouched by the fire — said Hoyas' hobby is to care for the plants.
"It's just so sad," said the other neighbor.
>> Staff Writer Darren Simon can be reached at 337-4082.