California residents who lit illegal fireworks over the July 4 holiday may be in for a nasty surprise in the mail thanks to covert fire department operations.

Homeowner Earl Decastro, 46, was nabbed and booked for involuntary manslaughter, though he has since posted his $25,000 bail.

The girl was fatally injured when a "large illegal fireworks display" set up by a local resident went awry, triggering an explosion, police said.