SAN FRANCISCO (KRON) — The FBI is asking the public’s help in locating vandals who have severed underground fiber optic cables at ten locations in the East and South Bay.

The FBI on Monday said the incidents occurred in Fremont, Walnut Creek, Alamo, Berkeley, and San Jose, dating back to a year ago. The most recent happened last Monday when vandals cut buried cables near the corner of Jones Road and Parkside Drive in Walnut Creek, according to investigators.

They say the individuals may appear to be telecommunications maintenance workers or they may be carrying tools consistent with that job role.

The FBI says it is working closely with Bay Area law enforcement agencies to find the people responsible.

The first case was reported 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, according to investigators.

Less than an hour later, the vandalism continued at Jones Road and Iron Horse Trail in Walnut Creek, and about 30 minutes after that, vandals returned to Fremont and cut cables at Niles Canyon Boulevard and Alameda Creek, federal officials said. A few hours later, during the predawn hours, vandals cut cables near Stockton and University avenues in San Jose.

Investigators say 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, 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 they targeted the site in Walnut Creek.

The FBI says that at this point, there is no indication these incidents are linked with the sabotage of the PG&E Metcalf substation back in April 2013.

Anyone with information about these cases is urged to contact the FBI at 415-553-7400 in the San Francisco area. The agency says all calls are confidential. Tips can also be submitted at: tips.fbi.gov.