Spectrum was hit first on Aug. 7 when fiber-optic lines were cut. A few days later, Verizon lines were also cut and stolen, leaving customers without phone and internet service.
Verizon service restored after fiber vandalism caused SoCal outage
Authorities say attacks targeting phone, internet and other communications infrastructure are increasing across the country. Last year, such incidents rose 59% nationwide, according to The Internet & Television Association.
Los Angeles led the nation in cable and wire thefts, with more than double the number reported in Houston, the second-highest city. Investigators point to the rising value of copper as a major factor behind the trend.
"You have crews that are just constantly doing this and ... I would say it's still an upward climbing trend," said Capt. Calvin Mah of the Los Angeles County Sheriff's Department Major Crimes Bureau.
Mah, who serves on the department's Metal Theft Detail, said the increasing price of copper has contributed to more theft attempts. Copper prices have climbed from just over $2 per pound a decade ago to $6.61 per pound today.
7 On Your Side digs into where stolen copper wire actually ends up. Here's what we found
AT&T has also been affected by copper thefts. The company said some of its copper was recently recovered at a metal recycling facility in South El Monte.
Mah said the facility owner told investigators he did not know the copper was stolen and believed it had come from a licensed vendor.
No arrests have been made, and detectives are continuing efforts to identify the seller.
Meanwhile, Spectrum and Verizon are offering separate $25,000 rewards for information leading to the conviction of those responsible for this month's cable thefts.
Authorities said a particularly frustrating aspect of the recent incidents is that the communications lines that knocked thousands of customers offline contained no copper and had little value to thieves.
"They're thinking they're stealing copper wire when in fact they're stealing fiber optics," Mah said. "But they don't know that at the time they're stealing it."