Also of concern for police is that rival gangs were working together on the operation.
Sgt. Timothy Tietjen, Fresno Police CCATT Team: "We've seen recently an increase in auto thefts, just in the last few weeks."
And now, FPD's Career Criminal Auto Theft Team expects those numbers will go down.
The auto thefts, and home burglaries this family is suspected of, had been occurring throughout the city.
And the operation was spread out as well...
It spanned three homes... One on Turner, near Leavenworth Elementary School, and another on Adler, near Kings Canyon and Willow.
"We believe that this crew of individuals are responsible for easily 8 to 10 vehicles a night."
During the bust, officers uncovered an ID theft operation, in which at least $9,000 was spent, just in the last week.
Police also seized several weapons, including an AK-47, cash, and hundreds of thousands of dollars worth of marijuana.
"They had grows within the garage. I mean, it's an extensive operation on all locations. And what you find is a whole family involved in preparing it, bagging it up for sales."
12 arrests have been made so far.
Most are members of the Ros family.
Police say at least two are affiliated with the Asian gang TRG, and one is a confirmed Bulldog gang member.
The charges being dished out include marijuana sales and possession, conspiracy, auto theft, and child endangerment.
"It's about money. It's not about gang affiliations. It's the career criminals that are looking for ways to make a profit and money."
Police expect Wednesday's arrests will put a significant dent in the recent rash of auto thefts and home burglaries that have been going on throughout the city.
Officers are looking at a 15% reduction in those crimes compared to last year.
Police say more arrests are on the way.
One suspect is outstanding, and that's the father of some of those arrested today.