MESA, AZ - A fire at a vacant Mesa house spread to a home next door early Sunday morning.
The fire started at a house near Gilbert Road and Southern Avenue around 2 a.m.
According to firefighters, no one lived at the home and it did not have any power to it so investigators are trying to determine how the fire started.
Mesa Fire Department Battalion Chief Fernando Valenzuela said the fire grew so big it spread to a shed behind the home and flames damaged the house next door which forced two people out of their home.
Valenzuela said someone called 911 after hearing an explosion and seeing smoke and flames.