Firefighters were at the home two minutes after the alarm at 11:19 a.m., but the house was already engulfed in flames.
Neighbors told them a woman was inside, but firefighters had difficulty entering the house because the back door was blocked.
Firefighters found Viera on the bathroom floor, the Waco Tribune-Herald reported.
The cause of the fire was still being investigated, said John Johnson, Waco Fire Department Chief.
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