The investigation began in late September in Arizona when a traffic stop near a copper mine turned up $300,000 worth of stolen copper inside a tractor trailer. The ingots were made of unrefined copper that had traces of gold and silver, and weighed more than 800 pounds each, the Los Angeles Daily News reported Tuesday.
"This is a brazen theft of large amounts of copper ingots," said Bart Graves, a spokesman for the Arizona Department of Public Safety. "These thieves just work with impunity, driving the stuff out on trucks."
Arizona officials traced the copper to the Port of Los Angeles where customs officials identified several cargo containers destined for Hong Kong labeled as scrap copper. In all, 145 tons of copper was recovered, Graves said.
No charges had been filed but investigators continued to work the case.