Martinez fireball started by teens playing with tennis balls they set on fire

MARTINEZ, Calif. - Fire investigators say the fire that engulfed a home and created a gigantic fireball started on Wednesday after three teenage boys were playing stick ball with a tennis ball they'd set on fire.

Investigators say the burning tennis ball landed in dry vegetation, starting the fire.

The explosions that people saw and heard were cars and propane tanks burning. Videos shows electrical wires sparking in the blaze.

The teens were taken into custody before being released back to their parents.

The Contra Costa County District Attorney's Office is reviewing the case. 

No one was injured in the fire, but three residents were displaced.