The FBI is asking for help in finding the people responsible for vandalizing buried fiber optic cables at 10 locations in the East and South Bay over the past year.
The most recent incident happened last Monday when vandals cut buried cables near the corner of Jones Road and Parkside Drive in Walnut Creek, according to the FBI.
FBI Special Agent Greg Wuthrich told NBC Bay Area that agents have some theories on what the vandals might be doing with the cables, but nothing specific to tell the public. He did say, however, that agents don't believe the vandals are selling the cables for their copper value. "We're trying to determine" what the vandals are doing with the cut cables, he added.
The recent string of vandalism dates back to last July, starting with cables being severed the night of July 6, 2014, near the corner of Seventh and Grayson streets in Berkeley.
Later that same night, cables were cut in Fremont near the corner of Niles Canyon and Mission boulevards at 11:39 p.m.
Less than an hour later, the vandalism continued at Jones Road and Iron Horse Trail in Walnut Creek, and about 30 minutes after that the vandals returned to Fremont and cut cables at Niles Canyon Boulevard and Alameda Creek.
Finally, the vandals cut cables near Stockton and University avenues in San Jose at 2:13 a.m.
There were no incidents after that string of vandalism until February of this year, when cables were cut twice along Niles Canyon Road in Fremont at about 11:30 p.m. on Feb. 24.
Then this month, the vandals returned to cut cables the night of June 8 near Danville Boulevard and Rudgear Road in Alamo, on Overacker Avenue and Mowry Avenue in Fremont, and the next day in Walnut Creek.
The FBI said the recent string of vandalism of underground cables is not believed to be related to the sabotage of the PG&E Metcalf substation near San Jose on April 16, 2013. In addition to cutting fiber optic lines at the substation, the saboteurs used a high-powered rifle to shoot out transformers there. Cutting the fiber optic cables there caused widespread phone outages, including for some emergency dispatch services.
The FBI is looking for any witnesses to the vandalism over the last year and is asking anyone with information to contact the San Francisco FBI field office at (415) 553-7400 or to leave a tip at tips.fbi.gov.
NBC Bay Area's Raji Ramanathan contributed to this report.