The months-long investigation was a partnership between the Hemet Police Department, Riverside County Sheriff's Department, and Department of Motor Vehicles investigators assigned to the Vehicle Dismantler Industry Strike Team.
A spike in catalytic converter thefts, costing victims thousands of dollars, kicked off the investigation, which saw authorities conduct unannounced business inspections, Hemet police said.
Officials said that "Operation Undercarriage" resulted in identifying several businesses that were conducting unlicensed auto dismantling, auto repairs, catalytic converter recycling, and some even purchasing illegally-obtained catalytic converters.
"During the investigation, tipsters and arrestees implicated other local businesses they claimed may be involved in illegally obtaining stolen catalytic converters," Hemet police posted on Facebook.
In all, 56 stolen catalytic converters were recovered, 10 citations were issued, four unlicensed dismantlers were identified, two unlicensed auto repair facilities were located, and three repair businesses were found to be in violation of state record-keeping laws.
Authorities also said that implicated businesses were educated on catalytic converter and metal theft laws, and how to properly maintain written records of catalytic converter sellers.