Fire investigators say they have not found evidence of a Molotov cocktail but are looking at the possibility of arson.
The 3-alarm fire started around 6:00 a.m. Tuesday morning and damaged three apartment units before fire crews could contain it.
The apartments are located at San Ramon and Sixth Street, just west of Fresno State.
Firefighters had to work quickly to stop the fire from spreading. It was burning very intensely from a downstairs apartment where it started. It quickly moved upstairs into a second unit and then to a building behind it.
Neighbors said they heard arguing coming from outside and then heard a window break immediately before the fire started.
Koby Johns with the Fresno Fire Department said, "We're preserving the scene for our arson investigator to look at it. They will be looking for a device, they'll be looking for burn patterns, doing what they need to do to figure exactly how this fire started."
Only the two people who lived in the lower unit were displaced; the other units damaged were vacant.
There were no injuries.
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